A Comparison of the Reactions of the SiSn, SiAg, and SiZn Binary Systems with L3i

Alloys of Si with elements such as Sn, Ag, or Zn may exhibit large specific and volumetric capacities when cycled electrochemically vs lithium. Combinatorial films of in the range have been prepared by magnetron sputtering, where M is Sn, Ag, or Zn. These films have been analyzed for structure, composition, and electrochemical performance. The electrochemical performance of the film is found to be dependent on the element M as well as the amount, , of the element in the film. The three Si-based binary systems are compared in terms of phases formed, amorphous vs crystalline structure, and capacity retention. It is found that electrodes which remain as a single amorphous phase during insertion and removal of Li exhibit superior capacity retention as compared to electrodes that form multiple or crystalline phases.