Preparation and characterization of three-dimensional tin thin-film anode with good cycle performance

Three-dimensional tin thin-film anode was prepared by electroless plating tin onto three-dimensional (3D) copper foam (which served as current collector), and characterized physically by SEM, EDS and XRD. Its electrochemical property and mechanism were studied by charge-discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The SEM and EDS results indicated that tin film with 500 nm thickness was formed over the whole surface of copper branches. The XRD results suggested that a new phase of Cu₆Sn₅ was formed between copper and tin. Besides the tin microflake structure of 500 nm thickness, the interaction effects of the copper foam and Cu₆Sn₅ phase formed between copper and tin resulted in good cycle performance with first discharge capacity of 737 mAh g^-1, 97% capacity retention after 20 cycles and still 84% after 40 cycles.