nature上关于复合材料的英文文献

Short communication

Highly stabilized alpha-NiCo(OH)2nanomaterials for high performance device application

Paulo Roberto Martins,AndréLuis Araújo Parussulo,Sergio Hiroshi Toma,Michele Aparecida Rocha,Henrique Eisi Toma,Koiti Araki *

Instituto de Química,Universidade de São Paulo,Av.Prof.Lineu Prestes,748,São Paulo,SP CEP 05508-000,Brazil

h i g h l i g h t s

g r a p h i c a l a b s t r a c t

nanomaterials.

a r t i c l e i n f o

Article history:

Received 14May 2012Received in revised form 15June 2012

Accepted 18June 2012

Available online 23June 2012Keywords:

Nickel hydroxide Mixed hydroxides Alpha-polymorph Nanoparticles

Nanostructured materials

a b s t r a c t

Improving the charge capacity,electrochemical reversibility and stability of anode materials are main challenges for the development of Ni-based rechargeable batteries and devices.The combination of cobalt,as additive,and electrode material nanostructuration revealed a very promising approach for this purpose.The new a -NiCo mixed hydroxide based electrodes exhibited high speci fic charge/discharge capacity (355e 714C g À1)and outstanding structural stability,withstanding up to 700redox cycles without any signi ficant phase transformation,as con firmed by cyclic voltammetry,electrochemical quartz crystal microbalance and X-ray diffractometry.In short,the nanostructured a -NiCo mixed hydroxide materials possess superior electrochemical properties and stability,being strong candidates for application in high performance batteries and devices.

Ó2012Elsevier B.V.All rights reserved.

1.Introduction

Nickel hydroxides have been explored as electroactive materials of sensors [1e 6],electrochromic devices [7]and rechargeable batteries [8,9].Many efforts have been directed to improve the conductivity and reversibility of the charge/discharge processes,and to enhance the speci fic charge capacity by incorporation of

transition and non-transition metal ions as additives (Al,Zn,Cd,Co and Mn),[10e 16]or by generating nanomaterials.Another possi-bility is by stabilizing and using the alpha-Ni(OH)2(a 4g ,433mA h g À1)instead of the conventional beta (b 4b ,289mA h g À1)polymorph,because of its superior electrochemical properties [17,18].

The addition of Co ions to Ni hydroxide electrodes is known to have bene ficial effects,reducing the mechanical stress during charge/discharge processes,thus preventing electrode failure,and increasing the charge density [19,20].However,the absence of the characteristic cobalt waves in the mixed NiCo hydroxides

*Corresponding author.Tel.:þ551130918513;fax:þ551138155640.E-mail address:koiaraki@p.br (K.

Araki).Contents lists available at SciVerse ScienceDirect

Journal of Power Sources

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0378-7753/$e see front matter Ó2012Elsevier B.V.All rights reserved./10.1016/j.jpowsour.2012.06.065

Journal of Power Sources 218(2012)1e 4