Tin–Transition Metal–Carbon Systems for Lithium-Ion Battery Negative Electrodes

Abstract

Magnetron cosputter deposited ternary libraries of Sn1−x−yMxCySn1−x−yMxCy ( M=TiM=Ti , V and Co) ( 0<x<0.500<y<0.50Sn1−xMxSn1−xMx binary systems shows an amorphous composition range where the specific capacity for lithium decreases with M content. Adding carbon to the amorphous binaries, to make ternaries, causes the precipitation of crystalline Sn in the cases when M=TiM=Ti or V, but not when M=CoM=Co . We believe this is because stable carbides of Ti and V exist but stable Co carbides do not. The sputtered Sn–Co–CSn–Co–C system was found to have a large amorphous range and the initial amorphous atomic arrangement in certain compositions are stable over at least 27 charge-discharge cycles of 600mAh∕g600mAh∕g . Crystalline Sn was found to precipitate in composition ranges having competitive specific capacity in the Sn–Ti–CSn–Ti–C and Sn–V–CSn–V–C libraries causing rearrangement of the atoms during cycling leading to poor capacity retention.