Silver alloying effect on the electrochemical behavior of Si–Zr thin film anodes

To improve the electrochemical performance of Si–Zr thin films, we have investigated the effect of the replacement of Zr by Ag in the films. The Si–Zr–Ag thin films were prepared by co-sputtering from each pure target and then analyzed for structure, composition and electrochemical performance. The Ag-containing films show a plateau like region in the charge–discharge profiles, while the steep slopes are seen in the Si–Zr film. The Si–Zr–Ag films also show high capacity and good rate capability compared to the Si–Zr film, maintaining a comparable capacity retention with cycles. The improved electrochemical performance of Si–Zr–Ag films is attributed to the highly dispersed Si phase in the film, which was induced by formation of Zr–Ag bonds, and the lower impedance exerted by Ag alloying.