Three-Dimensional Porous Copper-Tin Alloy Electrodes for Rechargeable Lithium Batteries

Three-dimensional (3D) foam structure of a Cu6Sn5 alloy was fabricated via an electrochemical deposition process. The walls of the foam structure are highly porous and consist of numerous small grains. When used as a negative electrode for a rechargeable lithium battery, the Cu6Sn5 samples delivered a reversible capacity of about 400 mA h g–1 up to 30 cycles. Further, these materials exhibit superior rate capability, attributed primarily to the unique porous structure and the large surface area for fast mass transport and rapid surface reactions. For instance, at a current drain of 10 mA cm–2 (20C rate), the obtainable capacity (220 mA h g–1) was more than 50 % of the capacity at 0.5 mA cm–2 (1C rate).