Electrochemical synthesis and lithium storage performance of Sn–Cu alloy on three-dimensional porous Cu substrate

Three-dimensional (3D) porous Cu with excellent mechanical strength and interconnected pores with a size of ~3μm is prepared by electroless plating and used as the substrate for Sn–Cu alloy electrodes. The charge/discharge test results indicate that the Sn–Cu alloy electrode on 3D porous Cu delivered large high-power specific capacity and excellent cycleability thanks to its porous structure. The morphology evolution of Sn–Cu alloy electrode on 3D porous Cu during charging/discharging is investigated by scanning electron microscope (SEM). The results demonstrate that the Sn–Cu alloy can reversibly expand and contract to some extent owing to the pore space that can accommodate volume variation, which is the main reason for its excellent electrochemical performance. Electrochemical impedance spectroscopy (EIS) is also used to characterize electrode resistance variation upon cycling. ► 3D porous Cu with stable and interconnected pores with the size of ~3 mm was produced by electroless plating. ► Sn-Cu alloy was electrodeposited in the 3D porous Cu and delivered excellent cycleability and large high-power capacity thanks to its porous structure. ► The porous structure can reversibly expand and contract during charging/discharging owing to the pores can accommodate the volume variation.