Cycle Life Enhancement in Cu-Sn Anodes

Abstract

This technical report summarizes the work on two different approaches that have been used to increase the cycle life of active-inactive composites in the copper-tin system. The first approach is to reduce the particle size of the active-inactive composities to the nano-scale (<100 nm). The second approach is the addition of extra elements that segregate to grain/phase boundaries and increase the cohesive strength of the boundary. Both approaches significantly improved the capacity retention of a Cu6Sn5 alloy. A larger improvement in capacity retention was exhibited by the addition of 10-wt.% iron compared to the reduction of the particle size to the nano-scale. The volumetric capacity of the Cu6Sn5 alloy containing 10 wt.% iron at 100 cycles is almost three times the theoretical capacity of graphite. The Cu6Sn5-10 wt.% Fe material has potential as a replacement anode for graphite in lithium-ion batteries.