Electrochemical properties of Cu₆Sn₅-C composite powders with mixture of Cu₅Sn₆@void@C yolk-shell, Cu₅Sn₆ alloy, and hollow carbon

SnO2-CuO-C composite powders consisting of hollow-structured particles are directly prepared using template-free spray pyrolysis. Reduction of the composite powders at 1000°C produces Cu₆Sn₅-C composite powders containing a mixture of Cu₅Sn₆@void@C yolk-shell, Cu₅Sn₆ alloy, and hollow carbon particles. In the yolk-shell powder, mobile Cu₅Sn₆ powder particle is located inside the hollow hard-carbon powder particle. The mean sizes of the Cu₅Sn₆ alloy and carbon powders are 0.7 and 1.6 μm, respectively. The submicron Cu₅Sn₆ alloy powders are coated with a uniformly thin carbon layer. 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^-1. The charge capacity of the composite powders slightly increases with increasing number of cycles during the first three cycles. The maximum charge capacity of the composite powders is 300 mAh g^-1. The charge capacity of the composite powders is 241 mAh g^-1 after 30 cycles, at which point the capacity retention is 80%. The unique particle structure and phase homogeneity improve the cycle properties of the composite alloy powders.