Electrochemical Properties of Cu₆Sn_5-C Composite Powders with Mixture of Cu₆Sn₆@void@C Yolk-Shell, Cu₅Sn₆ Alloy, and Hollow Carbon

摘要

SnO2-CuO-C composite powders consisting of hollow-structured particles are directly prepared usingtemplate-free spray pyrolysis. Reduction of the composite powders at 1000C produces Cu6Sn5-Ccomposite powders containing a mixture of Cu5Sn6@void@C yolk-shell, Cu5Sn6 alloy, and hollowcarbon particles. In the yolk-shell powder, mobile Cu5Sn6 powder particle is located inside the hollowhard-carbon powder particle. The mean sizes of the Cu5Sn6 alloy and carbon powders are 0.7 and 1.6m, respectively. The submicron Cu5Sn6 alloy powders are coated with a uniformly thin carbon layer.-1 The initial charge and discharge capacities of the composite powders are 254 and 578 mAh g ,-1 respectively, at a high current density of 300 mA g . The charge capacity of the composite powdersslightly increases with increasing number of cycles during the first three cycles. The maximum charge-1 capacity of the composite powders is 300 mAh g . The charge capacity of the composite powders is-1 241 mAh g after 30 cycles, at which point the capacity retention is 80%. The unique particle structureand phase homogeneity improve the cycle properties of the composite alloy powders.