Nano-scale (<100nm) Cu5Sn6 powders were prepared by a chemical method that used a NaBH4 solution to reduce the metal ions. A significant improvement in capacity retention was obtained in the nano-scale Cu6Sn5 alloy, compared to the alloy having micron-sized particles. The volumetric capacity of the nano-scale Cu6Sn5 alloy at 100 cycles was almost twice the theoretical capacity of graphite.