锂离子电池容量衰减机理和界面反应研究

Capacity Fade Mechanisms and SideReactions inLithium-Ion BatteriesPankaj Arorat and Ralph E. White Center For Electrochemical Engineering, Department of Chemical Engineering, University of South Carolina,Columbia, South Carolina 29208, USAABSTRACTThe capacity of a lithium-ion battery decreases during cycling. This capacity loss or fade occurs due to several different mechanisms which are due to or are associated with unwanted side reactions that occur in these batteries. These reactions occur during overcharge or overdischarge and cause electrolyte decomposition, passive film formation, active material dissolution, and other phenomena. These capacity loss mechanisms are not included in the present lithium-ion battery mathematical models available in the open literature. Consequently, these models cannot be used to predict cell performance during cycling and under abuse conditions. This article presents a review of the current literature on capacity fade mechanisms and attempts to describe the information needed and the directions that may be taken to include these mechanisms in advanced lithium-ion battery models。

锂离子电池容量衰减机理和界面反应研究作者：Pankaj Arorat and Ralph E. White美国，南卡罗来纳29208，哥伦比亚，南卡罗来纳州大学，化工学院化工系摘要锂电池在循环过程中，其容量会逐渐衰减。

而出现容量衰减主要归因于几个不同的机理，这些机理大多与电池内部的界面反应相关，这些反应持续性的发生在电池的充放电环节，并且引起电解液的分解、钝化膜的形成、活性材料的溶解等其它现象。

关于容量衰减的机理在目前公开的锂离子电池数学模型的文献中并未加以阐述，因此在锂电池循环过程中和处于苛刻的条件下，我们无法通过模型来对锂电池的性能作出有效的预测。

本篇文章将陈述容量衰减的机理，并且试着去解释其本质，为构建先进的锂电池模型指明方向。

lntroductionThe typical lithium-ion cell(Fig. 1) is made up of a coke or graphite negative electrode, an electrolyte which serves as an ionic path between electrodes and separates the two materials, and a metal oxide (such as LiCoO2, LiMn2O4, or LiNiO2) positive electrode. This secondary (rechargeable) lithium-ion cell has been commercialized only概论传统的锂电池由碳或石墨负极材料、作为电极间的离子传输通道的电解液、金属氧化物（例如LiCoO2、LiMn2O4、LiNiO2）正极材料三部分组成，这种二次（可充电）电池已经商业化。

依照这种原理制作的锂电池已recently.47 Batteries based on this concept have reached the consumer market, and lithium-ion electric vehicle batteries are under study in industry. The lithium-ion battery market has been in a period of tremendous growth ever since Sony introduced the first commercial cell in 1990.With energy density exceeding 130 Wh/kg (e.g., Matsushita CGR 17500)and cycle life of more than 1000 cycles (e.g., Sony 18650)in many cases, the lithium-ion battery system has become increasingly popular in applications ，such as cellular phones, portable computers, and camcorders. As more lithium-ion battery manufacturers enter the market and new materials are developed, cost reduction should spur growth in new applications. Several manufacturers such as Sony Corporation, Sanyo Electric Company, Matsushita Electric Industrial Company, Moli Energy Limited, and A&T Battery Corporation have started manufacturing lithium-ion batteries for cellular phones and laptop computers. Yoda has considered this advancement and described a future battery society in which the lithium-ion battery plays a dominant role.经形成稳定的消费者市场，同时锂离子动力电池也在进行工业化研究。

自从1990年，Sony制造出第一批商业化电池开始，锂电池市场开始进入繁荣时期。

由于具有超过130wh/kg（matsushita CGR 17500）的能量密度和超过1000次循环的优势，锂电池在移动电话、手提电脑、便携式摄像机等设备领域得到更加广泛的应用。

随着更多的锂电池生产商进入市场，新型材料也被陆续开发出来，同时成本控制也成为新产品增长的关键因素。

像索尼电器、三洋电器公司、松下电器、莫里能源有限公司（加拿大）、日本A&T 电器公司都已经在移动电话和便携式电脑等产业开始锂电池应用商业化。

Yoda也已经认识到锂电池的发展趋势，并且在将来的电池能源时代，锂离子电池将扮演者关键的角色。

Several mathematical models of these lithium-ion cells have been published.Unfortunately, none of these models include capacity fade processes explicitly in their mathematical description of battery behavior. The objective of the present work is to review the current understanding of the mechanisms of capacity fade in lithiumion batteries. Advances in modeling lithium-ion cells must result from improvements in the fundamental understanding of these processes and the collection of relevant experimental data.关于锂离子电池的数学模型，已经有相关文献进行阐述，然而遗憾的是至今没有一篇文献能就容量衰减机理进行明确解释，而本文将会在锂电池容量衰减机理进行详细阐述。

先进的锂电池模型必须建立在加深对这些过程的基本理解和实验数据的整理归纳的基础之上。

Some of the processes that are known to lead to capacity fade in lithium-ion cells are lithium deposition (overcharge conditions), electrolyte decomposition, active material dissolution, phase changes in the insertion electrode materials, and passive film formation over the electrode and current collector surfaces. Quantifying these degradation processes will improve the predictive capability of battery models ultimately leading to less expensive and higher quality batteries. Significant improvements are required in performance standards such as energy density and cycle life, while maintaining high environmental,safety, and cost standards. Such progress will require considerable advances in our understanding of electrode and electrolyte materials, and the fundamental physical and chemical processes that lead to capacity loss and resistance increase in commercial lithium-ion batteries. The process of developing mathematical models for lithiumion cells that contain these capacity fade processes not only provides a tool for battery design but also provides a means of understanding better how those processes occur.一些常见的引起锂电池容量衰减的因素包括1、锂枝晶的生成（过充电压条件下）2、电解液分解3、活性材料的溶解4、电极材料嵌锂过程中发生相变5、电极材料和集流体表面钝化膜的形成。