What Are Batteries, Fuel Cells, and Supercapacitors 锂离子电池、燃料电池、超级电容器
材料进化如何改变我们生活英语作文
材料进化如何改变我们生活英语作文Materials Evolution and Its Impact on Our LivesThe world we live in is constantly evolving, and the materials we use have played a significant role in shaping our everyday lives. From the ancient use of stone, wood, and clay to the modern-day advancements in technology, the evolution of materials has been a driving force behind the progress of human civilization. In this essay, we will explore how the evolution of materials has transformed our lives and the ways in which we interact with the world around us.One of the most significant impacts of materials evolution has been on the field of construction. Throughout history, the materials used in building structures have evolved from simple mud and straw to more sophisticated materials such as concrete, steel, and glass. The development of these advanced materials has allowed architects and engineers to design and construct taller, more durable, and more energy-efficient buildings. The use of steel, for example, has enabled the construction of skyscrapers that reach unprecedented heights, while the incorporation of glass has transformed the way we experience natural light and ventilation within our living and working spaces.Similarly, the evolution of materials has had a profound impact on the transportation industry. The invention of the wheel, for instance, revolutionized the way we move from one place to another, and the subsequent development of materials like rubber, metal, and plastic has led to the creation of vehicles that are more efficient, comfortable, and environmentally friendly. The introduction of lightweight and high-strength materials, such as carbon fiber, has further enhanced the performance and fuel efficiency of modern vehicles, making them more accessible and appealing to a wider range of consumers.The impact of materials evolution can also be seen in the field of healthcare. The development of new materials, such as titanium and biocompatible polymers, has enabled the creation of medical devices and implants that are more durable, less invasive, and better integrated with the human body. These advancements have significantly improved the quality of life for individuals with various medical conditions, allowing them to regain mobility, restore function, and enhance their overall well-being.Furthermore, the evolution of materials has had a significant impact on the way we communicate and access information. The invention of paper and the subsequent development of printing technologies have revolutionized the dissemination of knowledge, makinginformation more accessible to the masses. The more recent advancements in electronic materials, such as semiconductors and display technologies, have led to the creation of smartphones, tablets, and other digital devices that have become essential toolsfor communication, entertainment, and learning in our modern world.The evolution of materials has also had a profound impact on the way we produce and consume energy. The development of materials like solar cells, lithium-ion batteries, and fuel cells has enabled the creation of renewable energy sources that are more efficient, sustainable, and environmentally friendly than traditional fossil fuels. These advancements have not only reduced our reliance on non-renewable resources but also have the potential to mitigate the environmental impact of our energy consumption.In conclusion, the evolution of materials has been a driving force behind the progress of human civilization. From construction and transportation to healthcare and communication, the advancements in materials have transformed the way we live, work, and interact with the world around us. As we continue to explore new and innovative materials, it is clear that the future of our society will be shaped by the ongoing evolution of these essential building blocksof our world.。
纳米科学与技术英语
纳米科学与技术英语Delve into the fascinating realm of nanoscience and technology, where the small scale becomes the epicenter of innovation and discovery. This field, often dubbed as the "next industrial revolution," is reshaping our understanding of materials and their applications. At the nanoscale, the properties of materials can change dramatically, offering unprecedented opportunities in medicine, electronics, and energy.Imagine a world where cancer cells are targeted with precision using nanoparticles, or where electronic devices are so small they can be integrated into fabrics or even the human body. This is the potential of nanoscience and technology, a field that is pushing the boundaries of what we thought was possible. The manipulation of matter at the atomic and molecular scale has led to the development of materials with unique properties that can be tailored for specific applications.In medicine, nanotechnology is revolutionizing drug delivery systems, allowing for more effective treatments with fewer side effects. The ability to control the release of drugs at a cellular level can lead to a more personalized approach to healthcare. Moreover, nanotechnology is also paving the way for advanced imaging techniques that can detect diseases at their earliest stages.In the world of electronics, the miniaturization of components is reaching new heights with the help of nanoscience. This has implications for the development of faster, more efficient, and more powerful computing devices. The quest for smaller, more powerful devices is not just about consumer electronics; it's also about the potential to create smart systems that can interact with their environment in new and innovative ways.Energy production and storage are also being transformed by nanotechnology. The development of nanomaterials for solar cells, batteries, and fuel cells is leading to more efficient energy conversion and storage solutions. This could be a game-changer in the quest for sustainable and clean energy sources.The exploration of nanoscience and technology is not without its challenges. Ethical considerations, environmental impacts, and the potential for misuse are all topics that must be addressed as this field continues to evolve. However, the promise of nanoscience and technology is immense, and as researchers and engineers continue to unlock its secrets, we stand on the cusp of a new era of scientific and technological advancement.。
能源专业外文翻译--燃料电池及其发展前景1
外文原文：Fuel Cells and Their ProspectsA fuel cell is an electrochemical conversion device. It produces electricity fromfuel (on the anode side) and an oxidant (on the cathode side), which react in the presence of an electrolyte. The reactants flow into the cell, and the reaction products flow out of it, while the electrolyte remains within it. Fuel cells can operate virtually continuously as long as the necessary flows are maintained.Fuel cells are different from electrochemical cell batteries in that they consume reactant from an external source, which must be replenished--a thermodynamically open system. By contrast batteries store electrical energy chemically and hence represent a thermodynamically closed system.Many combinations of fuel and oxidant are possible. A hydrogen cell uses hydrogen as fuel and oxygen (usually from air) as oxidant. Other fuels include hydrocarbons and alcohols. Other oxidants include chlorine and chlorine dioxide.Fuel cell designA fuel cell works by catalysis, separating the component electrons and protonsof the reactant fuel, and forcing the electrons to travel though a circuit, hence converting them to electrical power. The catalyst typically comprises a platinum group metal or alloy. Another catalytic process takes the electrons back in, combining them with the protons and oxidant to form waste products (typically simple compounds like water and carbon dioxide).A typical fuel cell produces a voltage from 0.6 V to 0.7 V at full rated load.Voltage decreases as current increases, due to several factors:•Activation loss•Ohmic loss (voltage drop due to resistance of the cell components and interconnects)•Mass transport loss (depletion of reactants at catalyst sites under high loads, causing rapid loss of voltage)To deliver the desired amount of energy, the fuel cells can be combined in series and parallel circuits, where series yield higher voltage, and parallel allows a stronger current to be drawn. Such a design is called a fuel cell stack. Further, the cell surface area can be increased, to allow stronger current from each cell.Proton exchange fuel cellsIn the archetypal hydrogen–oxygen proton exchange membrane fuel cell (PEMFC) design, a proton-conducting polymer membrane, (the electrolyte), separates the anode and cathode sides. This was called a "solid polymer electrolyte fuel cell" (SPEFC) in the early 1970s, before the proton exchange mechanism was well-understood. (Notice that "polymer electrolyte membrane" and "proton exchange mechanism" result in the same acronym.)On the anode side, hydrogen diffuses to the anode catalyst where it later dissociates into protons and electrons. These protons often react with oxidants causing them to become what is commonly referred to as multi-facilitated proton membranes (MFPM). The protons are conducted through the membrane to the cathode, but the electrons are forced to travel in an external circuit (supplying power) because the membrane is electrically insulating. On the cathode catalyst, oxygen molecules react with the electrons (which have traveled through the external circuit) and protons to form water — in this example, the only waste product, either liquid or vapor.In addition to this pure hydrogen type, there are hydrocarbon fuels for fuel cells, including diesel, methanol (see: direct-methanol fuel cells and indirect methanol fuel cells) and chemical hydrides. The waste products with these types of fuel are carbon dioxide and water.The materials used in fuel cells differ by type. In a typical membrane electrode assembly (MEA), the electrode–bipolar plates are usually made of metal, nickel or carbon nanotubes, and are coated with a catalyst (like platinum, nano iron powders or palladium) for higher efficiency. Carbon paper separates them from the electrolyte. The electrolyte could be ceramic or a membrane.Oxygen ion exchange fuel cellsIn a solid oxide fuel cell design, the anode and cathode are separated by an electrolyte that is conductive to oxygen ions but non-conductive to electrons. The electrolyte is typically made from zirconia doped with yttria.On the cathode side, oxygen catalytically reacts with a supply of electrons to become oxygen ions, which diffuse through the electrolyte to the anode side. On the anode side, the oxygen ions react with hydrogen to form water and free electrons. A load connected externally between the anode and cathode completes the electrical circuit.Fuel cell design issuesCostsIn 2002, typical cells had a catalyst content of US$1000 per-kilowatt of electric power output. In 2008 UTC Power has 400kw Fuel cells for $1,000,000 per 400kW installed costs. The goal is to reduce the cost in order to compete with current market technologies including gasoline internal combustion engines. Many companies are working on techniques to reduce cost in a variety of ways including reducing the amount of platinum needed in each individual cell. Ballard Power Systems have experiments with a catalyst enhanced with carbon silk which allows a 30% reduction (1 mg/cm2 to 0.7 mg/cm2) in platinum usage without reduction in performance.The production costs of the PEM (proton exchange membrane). The Nafion membrane currently costs €400/m². In 2005 Ballard Power Systems announced that its fuel cells will use Solupor, a porous polyethylene film patented by DSM.Water and air management (in PEMFC). In this type of fuel cell, the membrane must be hydrated, requiring water to be evaporated at precisely the same rate that it is produced. If water is evaporated too quickly, the membrane dries, resistance across it increases, and eventually it will crack, creating a gas "short circuit" where hydrogen and oxygen combine directly, generating heat that will damage the fuel cell. If the water is evaporated too slowly, the electrodes will flood, preventing the reactants from reaching the catalyst and stopping the reaction. Methods to manage water in cells are being developed like electroosmotic pumps focusing on flow control. Just as in a combustion engine, a steady ratio between the reactant and oxygen is necessary to keep the fuel cell operating efficiently.Temperature managementThe same temperature must be maintained throughout the cell in order to prevent destruction of the cell through thermal loading. This is particularly challenging as the 2H2 + O2 =2H2O reaction is highly exothermic, so a large quantity of heat is generated within the fuel cell.Durability, service life, and special requirements for some type of cells Stationary fuel cell applications typically require more than 40,000 hours of reliable operation at a temperature of -35°C to40°C, while automotive fuel cells require a 5,000 hour lifespan (the equivalent of 150,000 miles) under extreme temperatures. Automotive engines must also be able to start reliably at -30 °C and have a high power to volume ratio (typically 2.5 kW per liter).HistoryThe principle of the fuel cell was discovered by German scientist Christian Friedrich Schönbein in 1838 and published in one of the scientific magazines of thetime. Based on this work, the first fuel cell was demonstrated by Welsh scientist Sir William Robert Grove in the February 1839 edition of the Philosophical Magazine and Journal of Science, and later sketched, in 1842, in the same journal. The fuel cell he made used similar materials to today's phosphoric-acid fuel cell.In 1955, W. Thomas Grubb, a chemist working for the General Electric Company (GE), further modified the original fuel cell design by using a sulphonated polystyrene ion-exchange membrane as the electrolyte. Three years later another GE chemist, Leonard Niedrach, devised a way of depositing platinum onto the membrane, which served as catalyst for the necessary hydrogen oxidation and oxygen reduction reactions. This became known as the“Grubb-Niedrach fuel cell”. GE went on to develop this technology with NASA and McDonnell Aircraft, leading to its use during Project Gemini. This was the first commercial use of a fuel cell. It wasn't until 1959 that British engineer Francis Thomas Bacon successfully developed a 5 kW stationary fuel cell. In 1959, a team led by Harry Ihrig built a 15 kW fuel cell tractor for Allis-Chalmers which was demonstrated across the US at state fairs. This system used potassium hydroxide as the electrolyte and compressed hydrogen and oxygen as the reactants. Later in 1959, Bacon and his colleagues demonstrated a practical five-kilowatt unit capable of powering a welding machine. In the 1960s, Pratt and Whitney licensed Bacon's U.S. patents for use in the U.S. space program to supply electricity and drinking water (hydrogen and oxygen being readily available from the spacecraft tanks).United Technologies Corporation's UTC Power subsidiary was the first company to manufacture and commercialize a large, stationary fuel cell system for use as a co-generation power plant in hospitals, universities and large office buildings. UTC Power continues to market this fuel cell as the PureCell 200, a 200 kW system (although soon to be replaced by a 400 kW version, expected for sale in late 2009). UTC Power continues to be the sole supplier of fuel cells to NASA for use in space vehicles, having supplied the Apollo missions, and currently the Space Shuttle program, and is developing fuel cells for automobiles, buses, and cell phone towers; the company has demonstrated the first fuel cell capable of starting under freezing conditions with its proton exchange membrane automotive fuel cell.Fuel cell efficiencyThe efficiency of a fuel cell is dependent on the amount of power drawn from it. Drawing more power means drawing more current, which increases the losses in the fuel cell. As a general rule, the more power (current) drawn, the lower the efficiency.Most losses manifest themselves as a voltage drop in the cell, so the efficiency of a cell is almost proportional to its voltage. For this reason, it is common to show graphs of voltage versus current (so-called polarization curves) for fuel cells. A typical cell running at 0.7 V has an efficiency of about 50%, meaning that 50% of the energy content of the hydrogen is converted into electrical energy; the remaining 50% will be converted into heat. (Depending on the fuel cell system design, some fuel might leave the system unreacted, constituting an additional loss.)For a hydrogen cell operating at standard conditions with no reactant leaks, the efficiency is equal to the cell voltage divided by 1.48 V, based on the enthalpy, or heating value, of the reaction. For the same cell, the second law efficiency is equal to cell voltage divided by 1.23 V. (This voltage varies with fuel used, and quality and temperature of the cell.) The difference between these numbers represents the difference between the reaction's enthalpy and Gibbs free energy. This difference always appears as heat, along with any losses in electrical conversion efficiency.Fuel cells do not operate on a thermal cycle. As such, they are not constrained, as combustion engines are, in the same way by thermodynamic limits, such as Carnot cycle efficiency. At times this is misrepresented by saying that fuel cells are exempt from the laws of thermodynamics, because most people think of thermodynamics in terms of combustion processes (enthalpy of formation). The laws of thermodynamics also hold for chemical processes (Gibbs free energy) like fuel cells, but the maximum theoretical efficiency is higher (83% efficient at 298K) than the Otto cycle thermal efficiency (60% for compression ratio of 10 and specific heat ratio of 1.4). Comparing limits imposed by thermodynamics is not a good predictor of practically achievable efficiencies. Also, if propulsion is the goal, electrical output of the fuel cell has to still be converted into mechanical power with the corresponding inefficiency. In reference to the exemption claim, the correct claim is that the "limitations imposed by the second law of thermodynamics on the operation of fuel cells are much less severe than the limitations imposed on conventional energy conversion systems". Consequently, they can have very high efficiencies in converting chemical energy to electrical energy, especially when they are operated at low power density, and using pure hydrogen and oxygen as reactants.In practice, for a fuel cell operating on air (rather than bottled oxygen), losses due to the air supply system must also be taken into account. This refers to the pressurization of the air and dehumidifying it. This reduces the efficiency significantlyand brings it near to that of a compression ignition engine. Furthermore fuel cell efficiency decreases as load increases.The tank-to-wheel efficiency of a fuel cell vehicle is about 45% at low loads and shows average values of about 36% when a driving cycle like the NEDC (New European Driving Cycle) is used as test procedure. The comparable NEDC value for a Diesel vehicle is 22%. In 2008 Honda released a car with fuel stack claiming a 60% tank-to-wheel efficiency.Fuel cells cannot store energy like a battery, but in some applications, such as stand-alone power plants based on discontinuous sources such as solar or wind power, they are combined with electrolyzers and storage systems to form an energy storage system. The overall efficiency (electricity to hydrogen and back to electricity) of such plants (known as round-trip efficiency) is between 30 and 50%, depending on conditions. While a much cheaper lead-acid battery might return about 90%, the electrolyzer/fuel cell system can store indefinite quantities of hydrogen, and is therefore better suited for long-term storage.中文译文：燃料电池及其发展前景燃料电池是一种电化学转换装置。
Fuel-cells简介图文(共38张PPT)
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B 固体炭燃料电池的探索
氢为燃料太贵，Grove之后许多学者对固体碳燃料电池进行了多方面 研究,但都未获成功
原因:
①碳很难进行电化学反应
②天然碳中含有灰分,不易清除且污染电解质 ③固体物质难于连续输送
第14页，共38页。
(3) SOFC, Solid oxide fuel cell
SOFC工作温度高达1000℃,反应速度快,不需要贵重金属做催化剂 不存在电解质腐蚀金属问题 碳氢化合物燃料可自动在燃料电池内部重整, 燃料中杂质对电池的性能、
寿命影响小 燃料转换效率高,高温余热可很好利用 主要问题： 固体氧化物电解质所用的陶瓷材料脆性大,目前仍很难制造出大面积
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3 燃料电池的发展
（1）试验室研究阶
段 相对比,内燃机的效率为22～23%。
主要开发项目：航天用碱性氢氧燃料电池。
1840～1952 90年代以来, 又一次燃料电池研究开发热潮
美、加、德、日等国已有近二十家公司从事电动车的研制和开发，采用Ballard公司的燃料电池从事电动车开发的公司有11家 (2) PAFC, phosphorous acid fuel cell 美国ERC公司早在70年代就进行MCFC研究, 80年代以后转为重点开发, 开发的2MW天然气内重整MCFC1994年底试运行, 1997年3月因
以上
理论转换效率：
G1TS
H H
第6页，共38页。
实际转换效率
第7页，共38页。
B 比能量和比功率高 封闭体系蓄电池与外界没有物质的交换, 比能量不会
专业英语(1)
一。
crankshaft 曲轴. piston活塞. cylinder 气缸. joint venture 合资企业. engine 发动机fuel-efficient 节能的hybrid 混合的lightweight 重量最轻的二。
chassis 底盘onboard车载的clutch 离合器. pan盘底盘. driveshaft传动轴主动轴. suspension 悬架. linkage 连杆机构.transaxle 驱动桥. turbocharger涡轮增压器.三。
block 气缸体. exhaust manifold 排气歧管.cam 凸轮. catalytic converter 催化转化器. muffer 消声器. resonator 辅助消声器. intake manifold 进气歧管. valve stem 气门杆. fuel vapor 燃油蒸气. timing chain 正时链条. fuel-injection system 燃油喷时系统srankshaft sprocket 曲轴链轮. vibration clamper 曲轴减震器. drive-belt pulley 皮带传动轮.nozzle 喷油嘴. radiator 散热器. throttle 节流阀coolant 冷却液四。
lubricant 润滑剂. shift lexer 换挡杆. synchronizer 同步器. rpm= revolutions per minute 转数/分.五。
bumper 缓冲器保险杠. shock absorber 缓冲器.减震器. fender 挡泥板. steering knwuckle 转向节. hood 车蓬引擎罩.六。
instument panel仪表板. winding 绕组. capacitor 电容器. spark plug 火花塞. condenser 电容器relay 继电器七。
电极材料 英语
电极材料英语In the realm of energy conversion and storage technologies, electrode materials play a pivotal role, influencing both performance and efficiency. As the needfor sustainable and efficient energy systems increases, the significance of electrode materials in fields like batteries, fuel cells, and supercapacitors is becoming increasingly apparent. In this article, we delve into the current status of electrode materials, exploring various types, their applications, and challenges, while alsolooking ahead to potential advancements and future trends.**Types of Electrode Materials**Electrode materials can be broadly categorized intothree types: metallic, carbon-based, and composite materials. Metallic electrodes, such as lithium, nickel,and cobalt, offer high energy densities but can suffer from issues like corrosion and dendrite formation. Carbon-based electrodes, including graphite, carbon nanotubes, and graphene, provide excellent conductivity and stability but may not offer the same level of energy density as metallics. Composite materials, which combine the benefits of bothmetallics and carbon-based materials, are being actively researched to address the limitations of both.**Applications of Electrode Materials**Electrode materials find applications across a range of electrochemical devices. In lithium-ion batteries (LIBs),for instance, they enable the storage and release of energy through redox reactions. In fuel cells, electrodes catalyze the conversion of chemical energy into electrical energy. Supercapacitors, on the other hand, rely on electrodes with high surface areas and conductivity to store charge rapidly. **Challenges and Future Trends**Despite their widespread use, electrode materials face several challenges. These include improving energy density, enhancing cycling stability, and reducing costs. To address these issues, researchers are exploring innovativematerials like silicon composites, sulfur cathodes, and metal oxides. These materials offer the potential forhigher energy densities and improved cycling stability, but they also come with their own set of challenges, such as volume expansion and instability.Looking ahead, the future of electrode materials islikely to be driven by the need for even more efficient and sustainable energy storage and conversion solutions. One promising trend is the development of solid-state batteries, which use solid electrolytes instead of liquid electrolytes. This innovation could lead to safer, faster-charging batteries with longer lifetimes. Another trend is the integration of electrode materials with other technologies, such as nanotechnology and artificial intelligence, to create more intelligent and adaptive energy systems.In conclusion, electrode materials are crucial to the advancement of energy conversion and storage technologies. As we move towards a more sustainable and efficient energy future, it is essential to continue exploring anddeveloping innovative electrode materials that can meet the demands of tomorrow's energy systems.**电极材料的现状与未来发展**在能源转换和储存技术领域，电极材料扮演着至关重要的角色，影响着能源系统的性能和效率。
HYDROGENFUELCELLS：氢燃料电池
HYDROGEN FUEL CELLSby Tom Dickerman/AHAWe are about to witness a most amazing event. Internal combustion engines (ICE’s), so abundant in the past century are about to be replaced by fuel cell systems over the next few decades. They will replace ICE’s for both vehicle power and for stationary power generation. Fuel cells will also replace batteries for small portable power supply. Hydrogen in an internal combustion engine(ICE) produces useable power at about 17 percent efficiency. A fuel cell system has about 50 percent efficiency. This makes the fuel cell about three times as efficient as an ICE! This explains the urgency to make fuel cells commercially available.The United States has spent more than $500 million in the development of highly efficient and environmentally benign fuel cells, according to Ed Gillis, the former director of fuel cell programs at the Electric Power Research Institute. While research continues, major commercialization efforts are underway at this time. Nearly every major car company in the world has invested massively in fuel cells for vehicles. Their total investment commitments now exceed two billion dollars, according to Peter Hoffman, publisher of the Hydrogen and Fuel Cell Newsletter.HOW FUEL CELLS WORKIn a typical fuel cell, hydrogen gas is supplied through a porous anode and oxygen or air is supplied through a porous cathode. An electrolyzer separates the two gases, which is a material that will not allow either of the gases to pass. On a molecular level, the hydrogen and oxygen have an affinity for each other, and would like to come together to create water (2 H2 + 02 = 2 H20).In this situation, the hydrogen atoms instantly give up their electrons, which then travel through an external circuit. The remaining parts of the hydrogen atoms are protons, which can now pass through the electrolyte, and connect with oxygen atoms. The receipt of free electrons from the external circuit allows the completion of the electrochemical reactions, as water is formed. The electrons traveling the electric circuit is electric current. Typically, a fuel cell produces about one volt when the circuit is open, which drops to a half volt when the circuit is closed and producing electrical power. For higher, more useful voltages, the fuel cells are usually stacked. One hundred cells in a stack yield about 50 volts of direct current. (DC)TYPES OF FUEL CELLSFuel cells are usually named for their electrolytes. To date five different electrolyte materials have shown potential for commercial development. The five fuel cell types have different characteristics, which make each one suitable for some applications but not others. A short description of the five types follows.ALKALINE FUEL CELLS (AFC’S)In 1839, W. R. Grove of Great Britain built the first fuel cell. He added a catalyst, potassium hydroxide, to water and put in the ends of two wires. By impressing direct electrical current, he split the water into hydrogen at one wire and oxygen at the other. This is called electrolysis of water. Then capturing both the hydrogen and oxygen, he found he could reverse the process, adding the hydrogen and oxygen at the two poles to re-create water and electric current. In this mode, he had a fuel cell.This first fuel cel l was called the alkaline fuel cell (AFC). In the 1960’s a more complex but highly reliable AFC stack was created for our manned spacecraft. AFC’s and phosphoric acid fuel cells (PAFC’S) provided essential drinking water, electricity and a little heat in the cold of outer space for the manned spacecraft Gemini, Apollo and the Space Shuttle Orbiter. Men and women could not have gone into space without them.An AFC and a PAFC from these flights are on exhibit at the National Air and Space Museum in Washington, DC.PHOSPHORIC ACID FUEL CELLS (PAFC’s)The next fuel cell to be developed was the phosphoric acid fuel cell. PAFC’s do not require pure oxygen, but can use air at the cathode. PAFC’s are now in use for electric power generation, notably at Kaiser Hospitals, air quality offices in California, and at various sites in Japan.PAFC’s are now being developed by the DOE (and others) for trucks, buses and railroad engines. Some PAFC’s are designed to take in methanol and reform it under heat and pressure, stripping off hydrogen for the anode fuel supply.PROTON EXCHANGE MEMBRANE (PEM) FUEL CELLS,ALSO KNOWN AS POLYMER ELECTROLYTE FUEL CELLS (PEFC’S)PEM’s have only a thin plastic membrane for their electrolyte. PEM’S can be very small, with high power densities. Taking away the waste heat in a uniform continuous way, so the membrane doesn’t burn up, is a significant engineering challenge, especially for high energy/power density designs.The most reliable PEM fuel cells to date have been built by Ballard Power Systems of Vancouver, Canada. Ballard has now sold its vehicle fuel cell division to Daimler-Benz. It is also possible that Toyota or another Japanese company may be the first to mass-produce a fuel cell car. Fuel cell cars with on-board hydrogen fuel will have virtually NO emissions, except a little steam, and will be very quiet. This will be the start of anenvironmental revolution, as we begin to replace all the dirty, inefficient internal combustion engines with clean, highly efficient fuel cell engines, worldwide.SOLID OXIDE FUEL CELLS (SOFC’s)Solid oxide fuel cells, which can only operate at high temperatures, are not suited for transportation, but for stationary power. They hold the promise of high fuel efficiency, high power density and low cost.SOFC’s can be of tubular or planar construction. For tubular designs, Westinghouse has completed many hours of successful operation. Ceramatics is a leader in planar SOFC’S, which are expected to have low cost, high performance and high reliability.MOLTEN CARBONATE FUEL CELLS (MCFC’s)Energy Research Corporation (ERC) and M-C Power Corporation are making important gains toward commercialization of molten carbonate fuel cells. Stacks have been tested and small demonstration plants have been completed. ERC also completed a large two-megawatt MCFC plant for the City of Santa Clara, California. Because of operating problems, the plant is not in use. It is believed the plant may have been scaled up to far from smaller prototypes, and that intermediate sized plants should have been built first, to help resolve engineering problems of scale.MARKET ENTRY FOR FUEL CELLS.Peter Bos, President of Polydyne, Inc, has analyzed costs of manufacturing various fuel cells, and the prices buyers are willing to pay for their fuel cell applications. According to Mr. Bos, the first fuel cells to enter the market will be for high value operations.This seems to be borne out by the history of fuel cells to date. The first to develop fuel cells were NASA and the military, which were willing to pay virtually any price for the fuel cells that met their needs. Fuel cells are now being marketed to remote sites where power demand is small, but reliability is crucial, such as remote weather and pollution monitoring stations. Kaiser hospitals have decided to use fuel cell plants for primary power for hospital life support systems, which must be highly reliable. Low noise levels and low pollution near hospitals were also key factors for Kaiser.Fuel cells will also be used early on for devices such as cellular phones, laptop computers and handheld camcorders. For such uses reliability, quietness, size and weight are more important considerations that the price. Fuel cells, with their almost unlimited shelf life, will soon be replacing conventional batteries, which often go dead before they are used. Throughout the third world, small villagers are pooling their scarce money to buy two appliances: a TV set and a small diesel or gasoline engine to run it. The fuel for the generator must often be carried twenty of fifty miles from the nearest fuel station. Hereis a market for solar photovoltaics. But what about at night, or when the weather is overcast? Often villagers also carry heavy lead acid batteries to their location.This is a very likely near-term market for fuel cells. With a small electolyzer and a solar panel, hydrogen can be made and stored in a small tank. At night, a fuel cell can then be operated to generate power on demand. No more twenty-mile walks to the nearest store; no more scarce money spent for fuel.Third world countries in general are good candidates for hydrogen and fuel cell systems, because they lack the competing power grids and natural gas pipelines of the West. They also lack the entrenched corporate interests that often block development of sustainable energy systems here in America.In the near future, solar-produced clean hydrogen fuel will also be used for cooking and heating in these countries, gradually bringing to a halt the gathering of firewood, which is now decimating many areas of the Planet. Trees can be planted without fear that they will be cut for firewood. Whole continents can regrow their trees. Such a prospect is very important for the mitigation of global warming.It is no exaggeration to say that hydrogen and fuel cell systems have the potential as critical tools both to counter global warming and to reverse other environmental damage, worldwide.The fuel cell revolution is coming. Fuel cells will be the engines/generators of choice for all uses in the twenty-first century. To paraphrase Lee Iacocca, we can lead or we can follow, or we can just get out of the way.FUEL CELL QUIZ1.FIVE TYPES OF FUEL CELLS ARE NEARING COMMERCIALIZATION.NAME THREE.a)ALKALINEb)ACIDc)SOLID OXIDEd)MOLTEN CARBONATEe)PROTON EXCHANGE MEMBRANE THREE COMPANIES THAT ARE RESEARCHING/DEVELOPING FUELCELLS.a)BALLARDb)DAIMLER-BENZc)WESTINGHOUSEd)M-C CORPORATIONe)TOYOTAf)CERAMATECg)ENERGY RESEARCH CORPORATION3.WHAT IS THE EFFICIENCY OF AN INTERNAL COMBUSTION ENGINE?a)17 PERCENT4.WHAT IS THE TYPICAL EFFICIENCY OF A FUEL CELL SYSTEM?a)50 PERCENT TWO APPLICATIONS FOR FUEL CELLS. WHICH ARE LIKELY TO BEEARLY ADOPTERS?a)CAMCORDERSb)LAPTOP COMPUTERSc)BATTERIESd)CELL PHONESe)REMOTE SITE APPLICATIONS6.IS HYDROGEN A FUEL?a)YES7.IS HYDROGEN COMMON IN NATURE?a)YES-MOST ABUNDANT ATOM IN THE UNIVERSE8.WHAT ARE ADVANTAGES OF A FUEL CELL OVER AN INTERNALCOMBUSTION ENGINE?a)THREE TIMES THE EFICIENCYb)NO DEPLETION OF FOSSIL FUELSc)NO AIR POLLUTIONd)NO CONTRIBUTION TO GLOBAL WARMING9.HOW CAN FUEL CELLS HELP TO MITIGATE GLOBAL WARMING?a)BY REPLACING FOSSIL FUELS, ELIMINATING THEIR CO2 EMISSIONSb)BY REPLACING THE USE OF FIREWOOD, STOPPING THE CUTTING OFTREES, WHICH SEQUESTER CARBON。
Fuel cell 燃料电池简介 英文
1
Introduction
2
Advantages
3
Classification
Contents
1
Introduction
2
Advantages
3
Classification
Fuel Cell Description
Fuel Cell Description
Changing energy
▪ Both use an electrolyte to conduct ions
Fuel Cells and Batteries Differences
▪ A battery is an energy storage device that has a fixed amount of chemical energy ▪ A fuel cell will keep producing electricity as long as fuel is supplied ▪ Fuel cell reactions do not degrade over time
Transportation Application
Contents
1
Introduction
2
Advantages
3
Classification
Environment Pollution
Environment Pollution has been a great threat.
Global warming
Obtaining electricity
Using air source
▪ At the anode a catalyst causes the fuel to undergo oxidation reactions that generate protons (positively charged hydrogen ions) and electrons. ▪ The protons flow from the anode to the cathode through the electrolyte after the reaction. At the same time, electrons are drawn from the anode to the cathode through an external circuit, producing direct current electricity. ▪ At the cathode, another catalyst causes hydrogen ions, electrons, and oxygen to react, forming water.
在火星生存很难的英语
在火星生存很难的英语Surviving on Mars: The Challenges and Potential Solutions.Venturing beyond Earth and establishing a sustainable human presence on Mars has long been a captivating aspiration for space exploration. However, the Martian environment poses formidable challenges that must be overcome to make this vision a reality. From the planet's thin atmosphere and extreme temperatures to its lack of liquid water and protection from harmful radiation, surviving and thriving on Mars requires ingenuity, technological advancements, and a comprehensive understanding of the planet's unique characteristics.The Challenges.Thin Atmosphere and Extreme Temperatures: Mars' atmosphere is incredibly thin, with a surface pressure only about 1% of Earth's. This lack of atmospheric pressureresults in extreme temperature variations, ranging from a scorching 70°C (158°F) during the day to a bone-chilling -63°C (-81°F) at night. Such drastic temperature fluctuations pose significant challenges for maintaining a stable and habitable environment for humans.Lack of Liquid Water: Mars is a remarkably arid planet, with no surface liquid water currently present. Water is essential for human survival, and its absence on Mars necessitates the development of innovative water extraction and recycling systems.Harmful Radiation: The Martian surface is exposed to high levels of cosmic and solar radiation due to its thin atmosphere and weak magnetic field. These radiations can be harmful to human health, increasing the risk of cancer and other adverse effects. Radiation shielding and protective measures are crucial for safeguarding astronauts on Mars.Dust Storms and Atmospheric Phenomena: Mars is prone to frequent and intense dust storms that can engulf the entire planet, blocking out sunlight and causing widespreaddisruption. These storms can reduce visibility, affect power generation, and pose respiratory hazards to humans.The Potential Solutions.Habitat Design and Thermal Management: To mitigate the challenges posed by Mars' thin atmosphere and extreme temperatures, habitats must be designed with advanced thermal insulation and temperature control systems. Pressurized modules can provide a breathable atmosphere and protection from temperature extremes, while airlocks and environmental control systems maintain a comfortable and livable interior.Water Extraction and Recycling: Water extraction technologies are essential for long-term human presence on Mars. Methods such as extracting water from the Martian atmosphere, subsurface ice, or mineral hydrates offer potential solutions to the water scarcity problem. Recycling and purification systems can also minimize water consumption and maximize its availability.Radiation Shielding: Providing adequate radiation shielding is paramount to protect astronauts from harmful radiation exposure. Habitats and spacesuits can be equipped with materials such as water, regolith, or composite shielding panels to absorb and deflect radiation. Advanced radiation detection and monitoring systems are also necessary to assess radiation levels and minimize risks.Dust Mitigation and Atmospheric Management: To address the challenges posed by dust storms, dust mitigation strategies such as electrostatic dust collectors or air filtration systems can be employed to minimize their impact on habitats and equipment. Atmospheric management systems can also be implemented to filter and purify the air, removing dust particles and other contaminants.Energy Generation and Power Management: Sustainable energy generation is crucial for powering habitats, life support systems, and exploration vehicles on Mars. Solar panels and nuclear reactors are potential sources of energy, while fuel cells and batteries can provide backup power during periods of darkness or reduced solar intensity.Food Production and Resource Utilization: Establishing a sustainable food production system is essential for long-term survival on Mars. Controlled environment agriculture (CEA) techniques can be employed to grow crops in enclosed and controlled environments, utilizing artificial lighting, hydroponics, and aeroponics. In-situ resource utilization (ISRU) technologies can also be used to extract and utilize Martian resources, such as water, oxygen, and building materials, reducing the need for supplies from Earth.Medical Care and Health Monitoring: A comprehensive healthcare system is necessary to ensure the well-being of astronauts on Mars. Advanced medical equipment, telemedicine capabilities, and trained medical personnel can provide essential care and support in remote and challenging conditions. Continuous health monitoring and screening are also crucial for detecting and addressing any potential health issues.Psychological and Social Support: Surviving on Mars requires not only technological solutions but alsopsychological and social support systems. Isolation, confinement, and the unique challenges of a Martian environment can affect astronauts' mental and emotional health. Establishing robust communication channels, providing opportunities for socialization and recreation, and fostering a sense of community are essential for maintaining their well-being.Conclusion.Establishing a sustainable human presence on Mars is an ambitious and complex endeavor that requires overcoming numerous challenges. By leveraging technological advancements, innovative solutions, and a comprehensive understanding of the Martian environment, we can mitigate these challenges and pave the way for future human exploration and settlement on the Red Planet. Embracing the spirit of ingenuity, collaboration, and perseverance will be instrumental in making the vision of living and thriving on Mars a reality.。
j power sources
J Power SourcesIntroductionJ Power Sources refers to the sources of power used in different applications. Power sources are essential for providing the necessary energy for various devices and systems to operate. The type of power source used depends on the specific requirements and constraints of the application. This document provides an overview of different J power sources, their advantages, disadvantages, and applications.1. BatteriesBatteries are one of the most common types of power sources used in numerous applications. They convert chemical energy into electrical energy. Batteries are portable, have a high energy density, and can be easily replaced when depleted. They are widely used in portable electronic devices such as smartphones, laptops, and smartwatches. They are also extensively used in automotive applications.Advantages of Batteries:•Portability•High Energy Density•Wide Range of Applications•Easy ReplacementDisadvantages of Batteries:•Limited Lifespan•Disposal and Recycling Challenges•Costly to Manufacture2. Fuel CellsFuel cells are electrochemical devices that convert the chemical energy from a fuel into electrical energy through a chemical reaction. They can use a variety of fuels, including hydrogen, methane, methanol, and more. Fuel cells are highly efficient and can operate continuously if supplied with fuel. They are used in various applications, including transportation, power plants, and portable power sources.Advantages of Fuel Cells:•High Efficiency•Environmentally Friendly (if hydrogen-based)•Continuous Operation with Fuel SupplyDisadvantages of Fuel Cells:•High Initial Cost•Limited Fuel Availability•Complex Refueling Infrastructure3. Solar PowerSolar power utilizes the energy from the sun to generate electricity. Photovoltaic (PV) cells convert sunlight directly into electrical energy. Solar power is a renewable and clean energy source. It is widely used in residential, commercial, and industrial applications for generating electricity and providing power to various devices.Advantages of Solar Power:•Renewable and Environmentally Friendly•Low Operating Costs•Long LifespanDisadvantages of Solar Power:•Dependence on Sunlight (Weather Conditions)•High Initial Installation Cost•Requires a Large Surface Area4. Wind PowerWind power harnesses the kinetic energy from the wind and converts it into electrical energy using wind turbines. Wind power is another renewable and clean energy source. It is commonly used in large-scale wind farms to generate electricity for communities and cities. It can also be utilized on a smaller scale for residential and commercial applications.Advantages of Wind Power:•Renewable and Environmentally Friendly•Scalable for Small or Large Applications•Low Operational CostsDisadvantages of Wind Power:•Dependence on Wind Availability•Potential Noise Pollution•Visual Impact on Landscapes5. Hydroelectric PowerHydroelectric power is generated by utilizing the gravitational force of falling or flowing water. It is one of the oldest and most widely used renewable energy sources. Hydroelectric power plants can range from small-scale installations tolarge-scale dams that generate electricity for entire regions. It is a reliable and clean energy source.Advantages of Hydroelectric Power:•Renewable and Environmentally Friendly•Reliable Power Generation•Water Storage and Flood ControlDisadvantages of Hydroelectric Power:•Limited Availability of Suitable Sites•Disruption of Aquatic Ecosystems•Initial Construction CostConclusionJ Power Sources play a crucial role in powering various applications. Batteries, fuel cells, solar power, wind power, and hydroelectric power are just a few examples of power sources used in different scenarios. Each power source has its unique advantages and disadvantages, making them suitable for specific applications. The choice of power source depends on factors such as energy requirements, portability, environmental impact, availability, and cost. As technology advances, there is a continuous search for more efficient and sustainable power sources to meet the growing energy demands of our society.。
燃料电池介绍中英文对照
纯燃料电池车只有燃料电池一个动力源，汽车的所有功率附和都有燃料电池承担。目前燃料电池汽车多采用混合驱动形式，在燃料电池的基础上，增加了一组电池或超级电容作为另一个动力源。主要结构有:能量控制单元，空气压缩机，燃料电池堆，高压储氢瓶，动力电池组，电动机。高压储氢瓶提供燃料,动力电池组提供而外的功率，让车加速、爬坡和高速运行。在车辆滑行时，能量控制单元将驱动电机变为发电机，从而将部分汽车动能变为电能给动力电池充电.也就是说采用混合动力形式后，不仅可以采用功率较小的电池系统,还可以实现制动能回收。还可以是燃料电池系统的运行工况相对比较稳定,有利提高燃料电池系统效率和寿命。
Fuelssence a kind of electric cars, in body，power transmission system, control system, etc., the fuel cell electric vehicle and general electric car basic same, the main difference is that the principle of power battery is different。Generally speaking，the fuel cell is through electrochemical reactions convert chemical energy into electricity, electrochemical reaction required reductant with hydrogen，oxygen oxidant is used，so the earliest development of fuel cell electric vehicle is more directly using hydrogen fuel, hydrogen storage can use liquefied hydrogen, compressed hydrogen or metal hydride hydrogen storage, etc.
交通工具以及它未来的变化英语作文
交通工具以及它未来的变化英语作文The Development of Transportation and its Future ChangesTransportation has always played a crucial role in human civilization, enabling people to travel faster and farther than ever before. From the invention of the wheel to the development of high-speed trains and electric cars, transportation technology has evolved significantly over the centuries. In this essay, we will explore the history of transportation and discuss its future changes.The earliest form of transportation was walking, followed by the use of domesticated animals for carrying goods and people. The invention of the wheel around 3500 B.C. revolutionized transportation, enabling people to transport heavy loads more efficiently. In ancient times, rivers and seas were important transportation routes for trade and travel, leading to the development of boats and ships.The next major innovation in transportation came with the invention of the steam engine in the 18th century, which powered steamboats and locomotives, revolutionizing land and sea transport. The 19th century saw the rise of the automobile industry, with the introduction of cars and motorcycles poweredby internal combustion engines. The invention of the airplane in the early 20th century further transformed transportation, making it possible to travel long distances in a fraction of the time.Today, transportation technology continues to advance rapidly, with the development of high-speed trains, electric vehicles, and autonomous vehicles. High-speed trains like the Shinkansen in Japan and the TGV in France can reach speeds of over 300 km/h, making them a fast and efficient mode of transportation for long-distance travel. Electric vehicles, powered by batteries or fuel cells, are becoming increasingly popular as a sustainable alternative to gasoline-powered cars. Autonomous vehicles, equipped with sensors and artificial intelligence, have the potential to revolutionize transportation by eliminating the need for human drivers.In the future, transportation is expected to become even more efficient, sustainable, and interconnected. One of the most anticipated changes in transportation is the development of hyperloop technology, which uses magnetic levitation and vacuum tubes to transport passengers and cargo atnear-supersonic speeds. Hyperloop systems could revolutionizelong-distance travel by reducing travel times significantly and minimizing carbon emissions.Another future change in transportation is the widespread adoption of electric and autonomous vehicles. As battery technology improves and charging infrastructure expands, electric vehicles are expected to become more affordable and practical for everyday use. Autonomous vehicles are also likely to become more common on the roads, offering safer and more efficient transportation options for passengers.In addition to technological advancements, transportation is also evolving in terms of infrastructure and urban planning. Cities around the world are investing in public transportation systems, bike lanes, and pedestrian-friendly streets to reduce traffic congestion and air pollution. Sustainable transportation solutions, such as bike-sharing programs and carpooling services, are becoming more popular as people seek environmentally friendly alternatives to driving.In conclusion, transportation technology has come a long way since the invention of the wheel, with advancements such as high-speed trains, electric vehicles, and autonomous vehicles shaping the way we travel today. As we look to the future, transportation is expected to continue evolving with thedevelopment of hyperloop technology, electric and autonomous vehicles, and sustainable urban planning. By embracing these changes, we can create a more efficient, sustainable, and interconnected transportation system for future generations.。
燃料电池测试英文文献
燃料电池测试英文文献Alright, here's a piece of writing in an informal and conversational tone, focusing on fuel cell testing, while adhering to the given guidelines:Fuel cell testing is a crucial step in ensuring the efficiency and reliability of these amazing energy-producing devices. You know, it's not just about putting them together and expecting them to work. We gotta make sure they're performing up to the mark.The first thing we do is give the fuel cells a good workout. We run them through a series of tests to see how they handle different conditions. It's like putting them through a fitness challenge to see if they can keep up.One of the tests we do is check their durability. We run them for extended periods to see if they can maintain their performance over time. It's kind of like a marathon for fuel cells, seeing if they can last the distance.Another important test is checking their response to different fuels. Not all fuels are created equal, and we want to make sure the fuel cells can handle a variety of them. It's like testing a car to see if it can run on both gas and diesel.Safety is always a big concern, so we also do tests to make sure the fuel cells are operating safely. We monitor them for any signs of leakage or overheating, ensuring they're not going to cause any trouble.In the end, all these tests help us fine-tune the fuel cells, improving their performance and ensuring they're ready for the real world. It's a lot of work, but it's worth it to have a reliable and efficient energy source.。
水热法制备不同形貌二硫化钼及其电化学电容性能
水热法制备不同形貌二硫化钼及其电化学电容性能武子茂;兰会林【摘要】以水热法制备不同形貌的二硫化钼电极材料,研究材料形貌对其电化学性能的影响.采用X射线衍射(XRD),扫描电子显微镜(SEM)和拉曼光谱(Raman)对制备的二硫化钼进行形貌、成分、结构表征,采用循环伏安法和恒电流充放电法测定纳米二硫化钼作为电极材料的电化学性能.结果表明:制备的不同形貌的二硫化钼中镂空网状二硫化钼的比电容高于三维花状二硫化钼以及空心球状二硫化钼和块状二硫化钼的比电容.三维花状二硫化钼和镂空状二硫化钼作为超级电容器的电极材料,具有较好的电化学电容性能,在电流密度为1 A/g、1 mol的Na2 SO4电解液中其比电容分别达到203、259 F/g.【期刊名称】《兰州理工大学学报》【年(卷),期】2016(042)005【总页数】5页(P18-22)【关键词】水热法;不同形貌的二硫化钼;超级电容器【作者】武子茂;兰会林【作者单位】兰州大学物理科学与技术学院,甘肃兰州 730000;兰州大学物理科学与技术学院,甘肃兰州 730000【正文语种】中文【中图分类】TB321近年来，能源问题越来越受到全球科学家的关注[1-2]，超级电容器作为一种新型储能设备，它具有较传统电容器高的比电容和能量密度，较电池高的功率密度，而且绿色环保，所以其具有非常广阔的应用前景[3-4].因此开发低成本大功率高能量密度的超级电容器成为研究热点，其中电极材料是研究的重点.近年来石墨烯[5]，金属氧化物[6-7]，金属硫化物[8]及他们的复合物[9-10]已成为超级电容器和锂离子电池的电极材料，特别是一些过渡族金属硫化物因其独特的物理化学特性而引起了科学家们广泛关注.过渡金属二硫化物MS2 (M=Mo,W,Nb,Ta,Ti,Re)因其独特的电学、磁学、光学及热学等特性在电容器、催化、锂电池、储氢析氢、光电、半导体等领域[11-15]有着广泛的应用前景.其中作为最具代表性的二硫化钼(MoS2 )因其独特的原子结构在多个领域引起了广泛关注， MoS2具有六方晶体层状结构，层与层之间由范德华力结合与石墨烯类似，层内由S—Mo—S三原子以共价键结合形成正六边形结构，厚度约为0.7 nm.MoS2由于比氧化物高的内在离子电导率[16]和比石墨高的理论比电容[17]，作为电容器的电极材料已经得到了人们深入的研究[11]. 采用热蒸发制备了MoS2薄膜，在1 mV/s扫描速度下获得了100 F/g的比电容.Hu等人[19]报道C/MoS2多孔管状纳米复合材料和纯块状MoS2在1 A/g的电流密度下的比电容分别为210、40 F/g.Huang等人[12]报道高分子聚苯胺与二维类石墨烯MoS2复合材料的比电容高达575 F/g，然而合成的纯二硫化钼在1 A/g电流密度下比电容只有98 F/g.Zhou等人[20]用水热法制备的花状二硫化钼纳米微球在1 A/g的电流密度下比电容达到122 F/g.然而这些二硫化钼电极材料的比电容性能并不令人十分满意，而且对于不同形貌MoS2的电容特性的研究也鲜有报道.因此本文通过水热法低成本合成了不同形貌的二硫化钼，并研究了它们的电化学电容性能的变化规律及各自的差异.1.1 MoO3的制备将1.05 g (NH4)6Mo7O24 分散在60 mL的去离子水中，强烈搅拌10 min，然后缓慢加入20 mL 2 mol 的HNO3.最后将混合溶液转入100 mL带有聚四氟乙烯衬底的不锈钢水热反应釜中密封，在180 ℃下水热反应24 h，然后使其自然冷却到室温，用去离子水、无水乙醇洗涤多次直到洗去多余的杂质，通过离心收集沉淀物.最终将产物在真空干燥箱中60 ℃干燥24 h.后面实验中用到的MoO3都是由此方法制备.1.2 不同形貌二硫化钼的制备块状二硫化钼的制备：将0.45 g MoO3 ，0.88 g KSCN分散在80 mL的去离子水中，磁力搅拌并缓慢加入1 mol的 HCl使溶液pH=3,搅拌1.5 h后将混合溶液转入100 mL带有聚四氟乙烯衬底的不锈钢水热反应釜中密封，在230 ℃下水热反应24 h，然后使其自然冷却到室温，用上面同样的方法洗涤干燥.空心球状二硫化钼的制备：将0.73 g Na2MoO4 ·2H2O ，0.88 g KSCN分散在80 mL的去离子水中，磁力搅拌溶液澄清时加入2.9 g C16H36BrN，然后再缓慢加入10 mol的HCl使溶液pH<1,搅拌1.5 h后将混合溶液转入100 mL带有聚四氟乙烯衬底的不锈钢水热反应釜中密封，在235 ℃下水热反应24 h，然后使其自然冷却到室温，用上面同样的方法洗涤干燥.花状二硫化钼的制备：将0.16 g 硫脲 CH4N2S 分散在60 mL去离子水中搅拌10 min，将0.16 g MoO3加入溶液中并超声10 min，磁力搅拌20 min.然后将混合溶液转入100 mL带有聚四氟乙烯衬底的不锈钢水热反应釜中密封，在180 ℃下水热反应48 h，然后使其自然冷却到室温，用上面同样的方法洗涤干燥.镂空网状二硫化钼的制备：将0.3 g MoO3和1.0 g硫代乙酰胺分散在80 mL的去离子水中，强烈搅拌20 min.然后将混合溶液转入100 mL带有聚四氟乙烯衬底的不锈钢水热反应釜中密封，在200 ℃下水热反应48 h，然后使其自然冷却到室温，用上面同样的方法洗涤干燥.1.3 材料的成分、结构、形貌及性能的表征利用场发射扫描电子显微镜(FE-SEM,Hitachi S-4800)，X射线衍射仪(XRD,Philips)，拉曼光谱仪(Horiba Jobin-Yvon LabRAM HR800)，能谱仪(EDS)对制备的二硫化钼进行形貌、晶体结构及成分表征.将制得的二硫化钼与乙炔黑、PVDF分别以8∶1∶1的质量比混合均匀，再加入溶剂NMP(N,N-二甲基吡咯烷酮)在玛瑙研钵中研磨均匀后涂于1.0 cm×1.0 cm的泡沫镍上，在烘箱中60 ℃干燥12 h后制成工作电极，以铂电极为对电极，Ag/AgCl为参比电极，1 mol/L的Na2SO4为电解液组成三电极测试系统，采用CH1660E电化学工作站(上海辰华)评价样品的电化学性能.2.1 前驱体 MoO3的形貌及物象表征图1为合成的纳米棒状MoO3的XRD图谱和场发射扫描电镜照片，从图1a可以看出所有的衍射峰与MoO3标准卡片一致(JCPDS 47-1320)，表明合成了结晶性很好的MoO3前驱体.从图1b可以看到，所有合成的MoO3是以纳米棒状的形貌存在，棒长4～6 μm、直径200 nm左右.2.2 不同形貌MoS2成分结构及形貌的表征图2为不同形貌二硫化钼的SEM照片.从图2a中可以看出一些块状的二硫化钼由一些薄的二硫化钼片连接起来，总体上合成的MoS2呈块状且比表面积较小，从图2b中可以看出，合成了空心球状二硫化钼球的表面有像毛绒状的二硫化钼纳米片，这增加了其比表面积，其详细的生长机理参见文献[21].从图2c中可以看出成功合成了花状二硫化钼，花瓣由大量片状的二硫化钼构成，花的直径约500 nm，其详细的生长机理参见文献[22].图2d中呈现的是由很多小的二硫化钼纳米片组成的镂空网状结构，这种结构增加了二硫化钼与电解液的接触面积.图3a为不同形貌MoS2的XRD图谱，可以看出，所有的衍射峰与MoS2标准卡片一致(JCPDS 37 -1492)，得到了具有六方晶系的MoS2，图中的字母K、Q、H、L分别表示块状、空心球状、花状、镂空网状二硫化钼(后面图中这些字母代表同样的意义不再一一说明).但是(103)晶面的特征峰随着形貌的变化逐渐消失，这可能是MoS2在不同实验条件下由于取向生长造成的，其余特征峰的强度也在随着形貌的变化逐渐变弱，这说明花状结构和镂空网状结构的MoS2结晶性不是很好.图3b是不同形貌MoS2的Raman图谱，面外振动模式A1g的峰位位于406cm-1，面内振动模式E2g的峰位位于383 cm-1.图3c为镂空网状MoS2的EDS图谱，图中显示除Mo和S元素之外，没有检测到其他元素.另外，测量到样品中所含Mo与S元素的原子比约为1∶2,这与MoS2的化学计量比一样，进一步说明所得样品为MoS2，其他形貌MoS2的EDS图谱与之相似不再一一列出.2.3 不同形貌二硫化钼电化学性能表征图4为4种不同形貌电极材料-0.9～-0.2 V扫描电位下，以不同扫描速率5、10、25、50、80、100 mV/s的循环伏安曲线，电解液为1 mol/L的Na2SO4溶液.从图中可以看出，所有形貌的CV曲线都没有氧化还原峰，表明MoS2具有典型的电双层电容器特性，此特性与文献[10～12] 的结果是一致.CV曲线在大的扫速下比小的扫速下拥有更大的积分面积.根据电极比电容公式算得随着扫描速率的增加,电极比电容降低，这是由于当扫描速率增加时，电极与电解质溶液界面的离子浓度快速增加，电解质从固/液界面扩散到电极材料内部的速度不足以满足电极材料的电化学反应，使得在电流增大时，活性物质利用率降低，导致比电容下降[23]. Cs=∫I(V)dv/vΔVm式中：∫I(V)dv为CV曲线的积分面积，v为扫面速率，ΔV为电位窗口，m为电极活性物质的质量.图5a为4种不同形貌电极材料在1 A/g电流密度下的恒电流充放电曲线.可以看到在1 A/g的电流密度下镂空网状、花状、空心球状、块状二硫化钼的比电容分别为37、129、203、259 F/g，它们依次降低，这可能是由于不同的形貌造成比表面积不同而引起的.Cs=It/ΔVm式中：I 为负载电流，t为放电时间，ΔV为放电过程中的电势改变，m为电极活性物质的质量.电极材料的比电容计算根据式(2)可得.图5b是不同形貌电极材料在电流密度分别为1、2、4、5、10 A/g下根据公式(2)算得的比电容.可以看到镂空网状、花状、空心球状、块状二硫化钼的比电容依次降低，比电容最大镂空网状二硫化钼在1、2、4、5、10 A/g时对应的比电容分别为259、200、153、144、99 F/g.比电容随着电流密度的增加而降低，这是由于在高的电流密度时，充放电只能够在部分电极表面进行，来不及充分充放电导致活性物质利用率降低引起比电容的下降.1) 采用水热法低成本合成了不同形貌的二硫化钼，分别研究了其电化学电容性能的变化规律及各自的差异，镂空网状二硫化钼因为其独特的纳米结构增加了活性物质与电解液的接触面积，减少了电子和质子在充放电过程中的扩散时间，提高了活性物质利用率从而提高了二硫化钼的比电容，使其在1、2、4、5、10 A/g时对应的比电容分别达到259、200、153、144、99 F/g.2) 镂空网状、花状、空心球状、块状二硫化钼的比电容依次降低，这可能是由于不同的形貌造成比表面积不同而引起的，在1 A/g的电流密度下对应的比电容分别为259、203、129、71 F/g.【相关文献】[1] ZHANG Y,LI J,KANG F,et al.Fabrication and electrochemical characterization of two-dimensional ordered nanoporous manganese oxide for supercapacitor applications[J].International Journal of Hydrogen Energy,2012,37(1):860-866.[2] ZHAO T,JIANG H,JAN M.Surfactant-assisted electrochemical deposition of α-cobalt hydroxide for supercapacitors [J].Journal of Power Sources,2011,196(2):860-864.[3] WINTER M,BRODD R J.What are batteries,fuel cells,and supercapacitors[J].Cheminform,2004,35(50):4245-4269.[4] KOTZ R,CARLEN M.Principles and applications of electrochemical capacitors[J].Electrochimica Acta,2000,45(15/16):2483-2498.[5] SUMBOJA A,FOO C Y,WANG X,et rge areal mass,flexible and free standing reduced graphene oxide/manganese dioxide paper for asymmetric supercapacitor device [J].Advanced Materials,2013,25(20):2809-2815.[6] ZHANG G,LOU X W.General solution growth of mesoporous NiCo2O4 nanosheets on various conductive substrates as high-performance electrodes for supercapacitors [J].Advanced Materials,2013,25(7):976-979.[7] 冉奋,赵磊,张宣宣,等.纳米棒状锰氧化物的制备及其电化学电容性能 [J].兰州理工大学学报2013,39(4):23-27.[8] YANG J,DUAN X,QIN Q,et al.Solvothermal synthesis of hierarchical flower-like β-NiS with excellent electrochemical performance for supercapacitors [J].J MaterChem,2013,1(16):7880-7884.[9] 郭铁明,王力群,李小成,等.三维石墨烯/泡沫镍基底上制备Ni掺杂Co(OH)2复合材料及其超电容性能 [J].兰州理工大学学报,2015,41(2):12-16.[10] HUANG K J,WANG L,LIU Y J,et yered MoS2 -graphene composites for supercapacitor applications with enhanced capacitive performance [J].International Journal of Hydrogen Energy,2013,38(32):14027-14034.[11] MA G,PENG H,MU J,et al.In situ intercalative polymerization of pyrrole in graphene analogue of MoS2 as advanced electrode material in supercapacitor [J].Journal of Power Sources,2013,229(1):72-78.[12] HUANG K J,LAN W,LIU Y J,et al.Synthesis of polyaniline/2-dimensional graphene analog MoS2 composites for high-performance supercapacitor [J].Electrochimica Acta,2013,109(11):587-594.[13] ZHOU W,YIN Z,DU Y,et al.Synthesis of few-layer MoS2 nanosheet-coated TiO2 nanobelt heterostructures for enhanced photocatalytic activities [J].Small,2013,9(1):140-147.[14] YIN Z Y,CHEN B,BOSMAN M,et al.Au nanoparticle-modified MoS2 nanosheet-based photoelectrochemical cells for water splitting [J].Small,2014,10(17):3537-3543.[15] SU D,DOU S,WANG G.WS2@graphene nanocomposites as anode materials for Na-ion batteries with enhanced electrochemical performances [J].Chemical Communications,2014,50(32):4192-4195.[16] HENG N F,BU X H,FENG PY.Synthetic design of crystalline inorganic chalcogenides exhibiting fast-ion conductivity [J].Nature,2003,426(6965):428-432.[17] XIAO J,CHOI D,COSIMBESCU L,et al.Exfoliated MoS2 nanocomposite as an anode material forlithium ion batteries [J].Chem Mater,2010,22(8):4522-4524.[18] JIA M S,LOH K P.Electrochemical double-layer capacitance of MoS2 nanowall films [J].Electrochemical and Solid-State Letters,2007,10(11):250-254.[19] HU B,QIN X,ASIRI A M,et al.Synthesis of porous tubular C/MoS2 nanocomposites and their application as a novel electrode material for supercapacitors with excellent cycling stability [J].Electrochimica Acta,2013,100(7):24-28.[20] ZHOU X,XU B,LIN Z,et al.Hydrothermal synthesis of flower-like MoS2 nanospheres for electrochemical supercapacitors[J].Journal of Nanoscience &Nanotechnology,2014,14(9):7250-7254.[21] 杨依萍,李卓民,杨玉超,等.二硫化钼中空微球的制备、表征以及光催化性能 [J].无机化学学报,2012,28(7):1513-1519.[22] WANG X,DING J,YAO S,et al.High supercapacitor and adsorption behaviors of flower-like MoS2 nanostructures [J].J Mater Chem A,2014,2(38):15958-15963.[23] 王兰.层状二硫化钼纳米复合材料在超级电容器中的应用 [D].信阳:信阳师范学院,2014.。
关于化学材料的英语作文
关于化学材料的英语作文英文回答：Chemical Materials: The Foundation of Modern Society.Chemical materials are the cornerstone of modern society, playing a critical role in every aspect of our lives. From the clothes we wear to the electronic devices we use, chemical materials are essential for our comfort, safety, and progress.The discovery and development of new chemical materials have revolutionized numerous industries and sectors over the years. From plastics and polymers to ceramics and semiconductors, chemical materials have enabled countless innovations and advancements, including:Transportation: Lightweight and durable plastics have significantly reduced the weight of vehicles, improvingfuel efficiency and reducing carbon emissions.Energy production: Advanced materials such as solar cells, batteries, and fuel cells are crucial for developing renewable and sustainable energy sources.Medicine: Polymers and biomaterials have led to advancements in medical devices, implants, and drugdelivery systems, improving healthcare outcomes.Electronics: Semiconductors and other electronic materials form the foundation of computers, smartphones, and other electronic devices that have revolutionized communication, information technology, and entertainment.Construction: Composites, ceramics, and advanced materials have improved the strength, durability, and sustainability of buildings and infrastructure.The development of new chemical materials is an ongoing process, driven by advancements in research and technology. By understanding the fundamental properties and behavior of materials, scientists and engineers can design and creatematerials with tailored properties for specific applications.The Importance of Chemical Materials Research.Research into chemical materials is crucial for the continued progress and development of modern society. By exploring new materials and refining existing ones, scientists and researchers can address global challenges such as climate change, energy scarcity, and the need for advanced technologies.Investment in chemical materials research has the potential to:Drive innovation: New materials can enable new technologies and products, fostering economic growth and creating employment opportunities.Enhance sustainability: Sustainable and environmentally friendly materials can help reduce our carbon footprint and promote a greener planet.Improve healthcare: Advanced materials can improve drug delivery, medical devices, and tissue engineering, leading to better health outcomes for all.Advance scientific discovery: The study of materials provides insights into fundamental scientific principles and can lead to breakthroughs in other disciplines.Secure the future: By developing new materials, we can ensure the availability of essential resources and technologies for future generations.中文回答：化学材料，现代社会的基石。
材料化学英文
材料化学英文Material Chemistry。
Material chemistry is a branch of chemistry that focuses on the study of the properties and behavior of different materials. It involves the understanding of the composition, structure, and properties of materials, as well as the development of new materials with specific properties for various applications. Material chemistry plays a crucial role in the advancement of technology and the development of new products in various industries, such as electronics, energy, healthcare, and environmental protection.One of the key areas of material chemistry is the study of the structure-property relationships of materials. This involves understanding how the atomic and molecular structure of a material influences its properties, such as strength, conductivity, and reactivity. By gaining insights into these relationships, scientists and engineers can design and develop materials with tailored properties to meet specific needs. For example, the development of lightweight and durable materials for aerospace applications requires a deep understanding of the structure-property relationships of materials.Another important aspect of material chemistry is the synthesis and characterization of materials. This involves the design and preparation of materials with desired properties, as well as the analysis of their chemical, physical, and mechanical properties. Material chemists use a variety of techniques, such as spectroscopy, microscopy, and diffraction,to characterize the structure and properties of materials at the atomic and molecular levels. This knowledge is essential for the development of new materials with improved performance and functionality.In addition, material chemistry plays a vital role in the development of advanced materials for energy storage and conversion. For example, the design and optimization of materials for lithium-ion batteries, fuel cells, and solar cells require a deep understanding of the electrochemical and optical properties of materials. Material chemists work on the development of new electrode materials, electrolytes, and photoactive materials to improve the efficiency and performance of energy devices.Furthermore, material chemistry is essential for the development of biomaterials for medical applications. Biomaterials are used in various medical devices and implants, such as artificial joints, dental implants, and tissue engineering scaffolds. Material chemists study the interactions between biomaterials and biological systems to design materials that are biocompatible, bioactive, and biodegradable. This requires a thorough understanding of the chemical and biological properties of materials to ensure their safety and effectiveness in medical applications.In conclusion, material chemistry is a multidisciplinary field that plays a crucial role in the development of new materials with tailored properties for various applications. By understanding the structure-property relationships of materials, synthesizing and characterizing materials, and developing advanced materials for energy and medical applications, material chemists contribute to the advancement of technology and the improvement of quality of life. The continuous development of new materials with enhanced properties will drive innovation and progress in the future.。
高三英语未来发展预测练习题30题
高三英语未来发展预测练习题30题1<背景文章>In recent years, artificial intelligence (AI) has been making significant progress and is expected to have a profound impact on various fields, including education. As we look to the future, the role of AI in education is becoming increasingly important.AI-powered tutoring systems can provide personalized learning experiences for students. By analyzing a student's learning style, strengths, and weaknesses, these systems can tailor educational content to meet the specific needs of each individual. For example, if a student struggles with a particular concept, the AI tutor can provide additional explanations and practice exercises until the student masters the concept.Moreover, AI can also be used to grade assignments and provide feedback to students. This not only saves teachers time but also allows for more timely and detailed feedback. Students can receive immediate feedback on their work, which can help them identify areas for improvement and make necessary adjustments.Another area where AI is likely to have a major impact is in adaptive learning. Adaptive learning platforms can adjust the difficulty level of the content based on a student's performance. If a student is finding thematerial too easy or too difficult, the platform can automatically adjust the level to ensure that the student is challenged but not overwhelmed.However, the integration of AI in education also raises some concerns. One concern is the potential for job displacement of teachers. As AI takes on more tasks traditionally performed by teachers, there is a fear that some teachers may lose their jobs. Another concern is the ethical implications of using AI in education. For example, there is a need to ensure that student data is protected and used appropriately.Despite these concerns, it is clear that AI has the potential to revolutionize education. By providing personalized learning experiences, timely feedback, and adaptive learning, AI can help students learn more effectively and efficiently.1. What can AI-powered tutoring systems do?A. Provide standardized learning experiences.B. Ignore a student's weaknesses.C. Tailor educational content to students' needs.D. Replace teachers completely.答案：C。
电池包名词中英对照
电池包名词中英对照（）单体] 电池 Cell原电池 Primary Cell蓄电池 Secondary Cell电池 Battery燃料电池 Fuel Cell锂电池 Lithium Cell熔融盐电池 Molten Salt Cell碱性电池 Alkaline Cell固体电解质电池 Solid electrolyte Cell非水电解质电池 non aqueous Cell指示电池 Pilot CellOem电池 OEM Battery替换电池 Replacement Battery储备电池 Reserve Cell应急电池 Emergency Battery缓冲电池 buffer Battery back-up Battery;电压标准电池 Standard Voltage Cell韦斯顿电压标准电池 Weston Standard Cell voltage 激活 Activation未激活的 Inactivated全密封电池 / hermetically sealed Cell极板 Plate涂膏式极板 pasted Plate极群 Plate Group负极板 negative Plate正极板 positive Plate管式极板 tubular Plate极群组 Plate Pack极板对 Plate pair隔离物 Spacer隔板 separator (Plate)阀 valve电池外壳 Cell can电池槽 Cell Case电池盖 Cell Lid电池封口剂 lid Sealing Compound整体电池 monobloc Battery整体槽 monoblock container边界绝缘体 Edge Insulator外套 Jacket单体电池 [] 电极 (cell) electrode端子 terminal端子保护套 terminal terminal protective cover; 负极端子 negative terminal正极端子 positive terminal电极的活性表面 Active surface of an electrode阳极 Anode阴极 cathode电解质 electrolyte电解质爬渗 electrolyte creep电解质保持能力 electrolyte containment 泄漏 leakage活性物质 Active material活性物质混合物 Active material Mix电池组合箱 Battery Tray输出电缆 output cable连接件 Connector矩形 Prismatic (in)圆柱形电池 Cylindrical Cell扣式电池 Coin Cell Button Cell;电化学反应 Electrochemical Reaction电极极化 electrode polarization反极 Cell Polarity reversal reversal结晶极化 Crystallization polarization活化极化 Activation polarization阳极极化 anodic polarization阴极极化 Cathodic polarizationMass Transfer 浓差极化 concentration polarization; polarization欧姆极化 Ohmic polarization反应极化 reaction polarization阳极反应 anodic Reaction阴极反应 Cathodic Reaction副反应 Side reaction; secondary reaction;容量 (电池的) capacity (for cells or batteries)额定容量 rated Capacity剩余容量 residual Capacity体积 (比) 容量 Volumetric Capacity温度系数 Temperature Coefficient (of the capacity)Mass (specific) capacity gravimetric capacityArea (ratio) capacity areic capacityBattery energy battery energy(cell) volume (ratio) energy volumic energy (related to battery)(battery) discharge discharge (of, a, battery)Discharge current discharge currentThe discharge rate is discharge rateShort circuit current (battery) short-circuit current (related, to, cells, or, batteries)Self discharge self dischargeDischarge voltage (battery) discharge, voltage (related, to, cells, or, batteries)Closed circuit voltage closed, circuit, voltageLoad voltage (rejection) on, load, voltage (deprecated)The initial discharge voltage is initial, discharge, voltageInitial closed circuit voltage initial, closed, circuit, voltageInitial load voltage (rejection) initial, on, load, voltage (deprecated)Termination voltage end-of-discharge voltage; final voltage; cut-off voltage; end-point voltageNominal voltage nominal voltageOpen circuit voltage (battery) open-circuit voltage (related to cells or batteries)Open circuit voltage temperature coefficient temperature, coefficient, of, the, open-circuit, voltageBit specific characteristicCharge retention capability charge retentionCapacity retention, capacity, retentionApparent internal resistance was internal, apparent, resistanceResidual active substance residual, active, massUse quality service massParallel parallel connectionAnd tandem parallel, series, connectionSeries series connectionSeries parallel series, parallel, connectionNominal value nominal valueBattery durability battery enduranceStorage test storage testService life service lifeStorage life storage life; shelf life;Continuous work test continuous, service, testMetal air battery air, metal, batteryAlkaline zinc air battery alkaline, zinc, air, batteryAlkaline zinc manganese dioxide battery alkaline, zinc, manganese, dioxide, batteryZinc silver oxide - zinc silver oxide batteries batteryNeutral zinc air battery neutral, electrolyte, zinc, air, batteryZinc chloride battery zinc, chloride, batteryZinc carbon battery zinc, carbon, batteryA galvanic cell such as a proton battery or a zinc chloride battery.482-04-08Leclanche battery Leclanch batteryThe salt electrolyte mainly consists of ammonium chloride and zinc chloride, the anode is manganese dioxide, and the negative electrode is the primary battery of zinc.482-04-09Lithium - carbon dioxide battery lithium, carbon, monofluoride, batteryA primary cell containing nonaqueous electrolyte, a positive electrode of carbon fluoride, and a negative electrode of lithium.482-04-10Lithium manganese dioxide battery lithium, manganese, dioxide, batteryLithium copper oxide battery lithium, copper, oxide, batteryPrimary battery containing nonaqueous electrolyte, anode copper oxide and negative electrode lithium.482-04-12Lithium iron disulphide lithium iron disulfide battery batteryLi-SOCl2 battery lithium thionyl chloride batteryDry cell dry cellPaperboard battery paper-lined cellPaste battery paste-lined cellCylindrical (primary) battery round cellLead acid battery lead, acid, batteryCadmium nickel batteries nickel, oxide, cadmium, battery, nickel, cadmium, batteryIron nickel battery, nickel, oxide, iron, battery, nickel, iron, batteryNickel oxide zinc battery zinc nickel battery; nickel zinc battery镉银蓄电池银氧化镉电池含碱性电解质，正极为氧化银，负极为镉的蓄电池。
1Fuel Cell Fundamentals
C hapter 1F uel Cell FundamentalsS. M. J avaid Z aidi and M. A bdur R aufAbstract In this chapter fuel cell introduction and general concepts about fuel cell are presented. Types of fuel cell and their classification are given and desired proper-ties of the polymeric membranes for use in PEMFC are described. At the end chal-lenges facing the fuel cell industry and their future outlook are briefly discussed. 1.1 IntroductionF uel cells are considered environment-benign technology providing solutions to a range of environmental challenges, such as harmful levels of local pollutants, in addition to providing economic benefits due to their high efficiency. Because of their potential to reduce the environmental impact and geopolitical consequences of the use of fossil fuels, fuel cells have emerged as potential alternatives to com-bustion engines.T he main advantages of the fuel cells are their pollution-free operation and high energy density [ 1]. They also have high energy conversion efficiency, low noise, and low maintenance costs [ 2]. Fossil fuel reserves are limited, and it has been predicted that the production of fossil fuels will peak around 2020 and then decline [ 3]. To meet the demand of food and energy of the ever-increasing popula-tion and to protect the environment from the ill effects of fossil fuel use [ 4], research and development in the area of fuel cells needs to be significant. The reported estimate of worldwide environmental damage is around $5 trillion annually [ 5]. Fuel cells are electrochemical devices that convert chemical energy of the fuel and oxidant directly into electricity and heat with high efficiency. Electrochemical processes in fuel cells are not governed by Carnot’s cycle; therefore, their operation is simple and more efficient compared with internal combustion (IC) engines. High efficiency makes fuel cells an attractive option for a wide range of applica-tions, including transportation, stationary, and portable electronic devices such as consumer electronics, laptop computers, video cameras, etc.A ll fuel cells consist of an anode, to which the fuel is supplied, a cathode, to which oxidant (e.g., oxygen) is supplied, and an electrolyte, which allows the flow of ions between the anode and cathode. The electrolyte should be highly resistive S.M.J. Zaidi, T. Matsuura (eds.) Polymer Membranes for Fuel Cells, 1 doi: 10.1007/978-0-387-73532-0, © Springer Science + Business Media, LLC 20092 S.M.J. Zaidi, M.A. Rauf to the electron current. The net chemical reaction is exactly the same as if the fuel were burnt, but by spatially separating the reactants, the fuel cell intercepts the stream of electrons that flow spontaneously from the fuel to the oxidant and diverts it for use in an external circuit. The fundamental driving force behind this process of ion migration is the concentration gradient between the two interfaces (electrode –e lectrolyte). The difference between a fuel cell and a conventional battery is that the fuel and oxidant are not integral parts of a fuel cell, but instead are supplied as needed to provide power to the external load. A fuel cell is “c harged ”as long as there is a supply of fuel to the cell, so self-discharge is absent. However, these are complicated systems and the voltage output of the typical polymer electrolyte membrane fuel cell (PEMFC) is around 0.7 V only [ 6].F or many years it was attempted to develop fuel cells as a power source. In the beginning they were developed mainly for space and defense applications. Attempts to develop earth-based systems were made during 1980s and 1990s. The recent drive for more efficient and environmentally friendly electrical generation techno-logies has resulted in substantial resources being diverted to fuel cell development. Presently fuel cell technology is maturing toward commercialization, but work still needs to be done in many fields. For commercial applications, component materials need to be developed and optimized to improve performance and lower costs. Long-term testing has to be done to obtain information on fuel cell performance. Furthermore, as fuel cell research moves on from laboratory-scale single cell studies to the development of application-ready stacks, new in situ measurement methods are needed for characterization and diagnostics.1.2 Fuel Cell ClassificationF uel cells are classified based on the type of electrolyte they use. The six most com-mon fuel cell types are:1. P olymer electrolyte membrane fuel cells (PEMFC)2. D irect methanol fuel cells (DMFC)3. A lkaline fuel cells (AFC)4. P hosphoric acid fuel cells (PAFC)5. M olten carbonate fuel cells (MCFC)6. S olid oxide fuel cells (SOFC)D MFC is the fuel cell that is similar to PEMFC, except that it uses methanol as the fuel directly on the anode instead of hydrogen or hydrogen-rich gas. The character-istics of these types of fuel cells are summarized in Table 1.1 .A mong the various types of fuel cells listed in the preceding, the PEMFC, which uses a sheet of polymer membrane as the solid electrolyte, is the subject of this book. The solid polymer electrolyte membrane is the most important constituent of these fuel cells that allows protons, but not electrons, to pass through. These fuel cells currently use perfluorinated Nafion ®membranes (Du Pont), which exhibit a number of shortcomings to optimum efficiency. Also, the polymer membranes rep-resent approximately 30% of the material cost of the fuel cell. The membrane in1 Fuel Cell Fundamentals3PEMFC functions twofold, it acts as the electrolyte that provides ionic communica-tion between the anode and cathode, and also serves as a separator for the two reactant gases. Both optimized proton and water membrane transport properties and proper water management are crucial for efficient fuel cell operation. Dehydration of the membrane reduces proton conductivity, and excess water can flood the elec-trodes. Both conditions may result in poor cell performance.A typical PEM fuel cell uses hydrogen as the fuel and oxygen/air as the oxidant. For hydrogen, a separate reformer reactor is required. Some fuel cells use methanol as fuel. In this case there is no need of a reformer, and the fuel cell is called a DMFC. In effect, DMFC is a special iteration of PEMFC. Its low temperature and pressure operation coupled with the low cost of methanol are attributes that makes DMFC a promising energy source [ 7 ].1.3 Membrane MaterialsE ver since the invention of ion exchange membranes as electrolyte for fuel cells in the 1950s, researchers were challenged to find the ideal membrane material to withstand the harsh fuel cell operating environment. Since then numerous attempt have been made to optimize membrane properties for application in fuel cells. The desired properties for use as a proton conductor in DMFC essentially include the following:1. C hemical and electrochemical stability in the cell operating environment (high resistance to oxidation, reduction, and hydrolysis)2. M echanical strength and stability in the cell operating environment3. C hemical properties compatible with the bonding requirements of the membrane electrode assembly (MEA)4. E xtremely low permeability to reactant gases to minimize columbic inefficiency5. H igh water transport to maintain uniform water content and prevent localized drying6. H igh proton conductivity to support high currents with minimal resistive losses and zero electronic conductivity7. P roduction costs compatible with the applicationT able 1.1 T ypes of fuel cells and their characteristicsS uitable applications F uel celltypeO perating tempe-rature ( °C ) E fficiency D omestic power S mall scale power L arge scale cogeneration T ransport A FC50 –90 50 –70 √√X √P EMFC50 –120 40 –50 √√X √P AFC175 –220 40 –45 X √X X M CFC600 –650 50 –60 X √√X S OFC 800 –1,000 50 –60 √√√X4 S.M.J. Zaidi, M.A. Rauf1.4 Fuel Cell ChallengesAlthough great improvements in fuel cell design and components have been made over the past years, several issues remain to be addressed before PEM fuel cells can become competitive enough to be used commercially. A major hurdle is the fuel, which is mostly hydrogen. PEMFCs run best on very pure hydrogen. Hydrogen obtained from hydrocarbons tends to contain small amount of carbon monoxide (CO), which have disastrous effects on the efficiency of anode reaction. Moreover, the onboard storage of hydrogen is problematic, whereas alternatives such as the on-board reformation of methanol complicate the system and reduce efficiency. The simpler DMFC, in which methanol is used as a fuel instead of hydrogen, suf-fers from the poor kinetics of methanol oxidation reaction at low temperatures and a high methanol permeation rate through the membrane. Finally, the overall cost of the fuel cell with its platinum-based catalyst, and problems with the currently used membranes (e.g., methanol permeation, high temperature stability, and high mem-brane cost) thwart the commercialization of fuel cells. Cost is a significant factor hindering the full commercialization of PEM fuel cells. In 2002, the cost of the catalyst itself was $1,000 per kW of electrical power output. This was cut down to $30 by 2007 .T o address PEMFC design issues, research in PEM fuel cells is being conducted by various scientific groups and automobile companies worldwide. It is today’s hot topic. The research in polymer fuel cells has been very impressive, as can be seen by the number of patents issued every year. There has been exponential growth in the number of PEM fuel cell patents over the last few years. Many new materials have been developed to improve performance of the fuel cell stack. Enhanced mod-eling activities have facilitated the design of better-performance components for fuel cell. With the growing number of patents in PEM fuel cell area, one can guess how much research had been done and technological advances have been achieved over the last few years (Fig. 1.1).F ig. 1.1G rowth in research activity of PEM fuel cell represented as a plot of number of patents per year1990199119921993199419951996199719981999200020012002200320042005YearN u m b e r o f P a t e n t s1 Fuel Cell Fundamentals 5 1.5 Future OutlookT he future of the PEM fuel cell strongly depends on the technological solution of the challenges facing the fuel cell industry. Academic organizations are looking into the technological aspects, while industries are looking into the involved cost factors. Right now the automotive industry is the largest investor in PEM fuel cell development. Other main areas of PEM applications are distributed power genera-tion and portable electronics [ 8]. PEM fuel cells were tested in the buses of V ancouver and Chicago at the end of the last century. The fuel cell market is growing, and between 2003 and 2005 an annual growth rate of about 18.7% was reported in the literature. The recent Worldwide Fuel Cell Industry Survey shows that sales remain at $331 million with an increase in R&D expenditure by 9% to $716 million from 2003 to 2004 [ 9]. Proton exchange membrane fuel cells dominated the industry as a key focus area. There has been a tremendous increase in R&D funding from virtually zero 30 years ago to about $400 million now spent annually by the U.S. government alone on hydrogen and fuel cell —r elated programs. In the United States, the year 2006 marked the launch of the President’s Advanced Energy Initiative, which provided for a 22% increase in funding for clean energy technology research, including hydrogen and fuel cell technologies, at the U.S. Department of Energy (DOE). Industry has already sought roughly 600 fuel cell vehicles to date. Stationary fuel cell systems also continue to make progress with record-setting installations worldwide.I t is projected that worldwide around 550 GW of generating capacity will be installed during 2000 –2010 [ 2]. Buses running on PEM fuel cells are being demon-strated in North America, Japan, Australia, and Europe. These were shown to have smooth acceleration with heavy passenger loads. China, one of the largest potential fuel cell markets in the world, is considering deploying fuel cell buses for the Beijing Olympic Games in 2008. Buses are being built by New Flyer for which Hydrogenics is the fuel cell system using 180 kW PEM fuel cells. With crude oil reserves being limited, and various environmental protection agencies imposing stricter environmental regulations, the highly efficient PEM fuel cell can hope to have a good market in the near future.R eferences1. Y an, Q., H. Toghiani, H. Causey, “S teady state and dynamic performance of proton exchangemembrane fuel cells (PEMFCs) under various operating conditions and load changes ”, J. Power Sources161 (2006) 492 –502.2. S mitha, B., S. Sridhar, A. A. Khan, “S olid polymer electrolyte membranes for fuel cell appli-cations —A review ”,J. Membr. Sci.259 (2005) 10 –26.3. S opian, K., A. H Shamsuddin, T. N. Veziroglu, “S olar hydrogen energy option for MalaysiaProceeding of the international conference on advances in stratic technology, June 1995 ”, U KM, Bangi(1995) 209 –220.6 S.M.J. Zaidi, M.A. Rauf 4. K ordesch, K. V., G. R. Simader, “E nvironmental impact of fuel cell technology ”,C hem. Rev.95 (1995) 191 –207.5. B arbir, F., “P EM fuel cells: Theory and practice ”,C alifornia: Elsevier Academic Press,(2005).6. I ojoiu, C., F. Chabert, M. Marechal, N. El. Kissi, J. Guindet, J. Y. Sanchez, “F rom polymerchemistry to membrane elaboration —A global approach of fuel cell polymeric electrolytes ”, J. Power Sources153 (2006) 198 –209.7. G e, J., H. Liu, “E xperimental studies of a direct methanol fuel cell ”,J. Power Sources142(2005) 56 –69.8. W ang, L., A. Husar, T. Zhou, H. Liu, “A parametric study of PEM fuel cell performances ”,I nt. J. Hydrogen Energy28 (2003) 1263 –1272.9. S atyapal, S., Proc: Fuel Cell Seminar 2006 Abstracts, November 13 –17, Hawai, USA(2006).。
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Applications
• Fuel cells established their usefulness in space applications with the advent of the Gemini and Apollo space programs • Fuel cells cannot compete today with combustion engines and gas/steam turbines because of much higher costs, inferior power and energy performance, and insufficient durability and lifetime
Batteries
• Electrical energy is generated by conversion of chemical energy via redox reactions at the anode and cathode • Closed systems, with the anode and cathode being the charge-transfer medium and taking an active role in the redox reaction as “active masses” • Energy storage and conversion occur in the same compartment • Batteries have intermediate power and energy characteristics • Batteries with thin film electrodes exhibit power characteristics similar to those of supercapacitors
Fuel cells
• Electrical energy is generated by conversion of chemical energy via redox reactions at the anode and cathode • Fuel cells are open systems where the anode and cathode are just charge-transfer media • The active masses undergoing the redox reaction are delivered from outside the cell • Energy storage (in the tank) and energy conversion (in the fuel cell) are thus locally separated • Fuel cells can be considered to be high-energy systems
Electrochemical capacitors
• By orientation of electrolyte ions at the electrolyte/electrolyte interface, so-called electrical double layers (EDLs) are formed and released, which results in a parallel movement of electrons in the external wire, that is, in the energy-delivering process • Supercapacitors are considered to be high-power systems
What Are Batteries, Fuel Cells, and Supercapacitors
Presented By Rex Lee
Introduction：Batteries，Fuel Cells，Supercapacitors
• Fossil fuels” consumption/production is forecast to have a severe future impact on world economics and ecology • Electrochemical energy production is under serious consideration as an alternative energy/power source, as long as this energy consumption is designed to be more sustainable and more environmentally friendly • Systems for electrochemical energy storage and conversion include batteries, fuel cells, and electrochemical capacitors (ECs)
Applications
• Batteries have an established market position • Supercapacitors have found niche markets as memory protection in several electronic devices • fuel cells are basically still in the development stage and are searching to find a “killer application” that allows their penetration into the market
Common features of these three systems
• The energy-providing processes take place at the phase boundary of the electrode\electrolyte interface • Electron and ion transport are separated • Consist of two electrodes in contact with an electrolyte solution • The requirements on electron and ion conduction in electrodes and the electrolyte are ttical values of energy content differ and are significantly lower than the theoretical values • The practical energy content of a rechargeable battery is 25% of its theoretical value, whereas a primary battery system can yield >50% of its theoretical value in delivered energy
Virtue
• However, as batteries and fuel cells are not subject to the Carnot cycle limitations, they may operate with much higher efficiencies than combustion engines and related devices
The origin of the difference
• The difference between thetheoretical and practical energy storage capabilities is related to several factors, including (1) inert parts of the system such as conductive diluents, current collectors, containers, etc., that are necessary for its operation, (2) internal resistances within the electrodes and electrolyte and between other cell/battery components, resulting in internal losses, and (3) limited utilization of the active masses, as, for example, parts of the fuel in a fuel cell leave the cell without reaction or as, for example, passivation of electrodes makes them (partially) electrochemically inactive
Applications
• Supercapacitor and fuel cell development aim to compete with, or even to replace, batteries in several application areas • High power and high energy (and thus a competitive behavior in comparison to combustion engines and turbines) can best be achieved when the available electrochemical power systems are combined
Energy contents and Rate capability