2003 Volume 71 Issue 12 Pages 1123-1125
Several kinds of metal films have a rate enhancing effect for Li insertion/extraction reaction when deposited on graphitized carbon. Ag, In, and Zn improved the reaction rates, whereas Au, Sn and Cu caused cycleability degradation. For Au and Sn this poor cycleability could be attributed for Au and Sn to the crystal collapse caused by a volume expansion due to the formation of Li alloys, whereas Cu yielded no alloys. Deposition of a Ag film over the surface of the Cu film recovered cycleability to a favorable level. Further deposition of a Cu film resulted in poor cycleability, which was again recovered by further covering with a Ag film. These results can be explained based on the insufficient property of the SEI formed on the Cu surface.