Electrochemical characteristics of Co-Si alloy and multilayer films as anodes for lithium ion microbatteries

The cycling behaviors of Co-Si alloy and multilayered films, which were prepared by co-deposition from separate pure metal sources and by alternating deposition of different metals, respectively, are investigated. The alloy films with near stoichiometric compound composition of CoSi2.06 and CoSi2.2 exhibit an excellent cycling stability, but alloying with large excess Si results in capacity fading during cycling. The cycling stability of multilayers with average composition of CoSi2.9 is improved significantly by post-annealing treatment at 350 degreesC. Nano-structured multilayer films are suggested as promising anode materials for thin-film batteries. (C) 2003 Elsevier Science Ltd. All rights reserved.