High rate capability of Cu-coated activated carbon electrodes for Li-ion capacitors using non-aqueous electrolytes

A novel type surface modified activated carbon (AC) was prepared using the electroless deposition method as a new attempt to modify AC for Li-ion capacitors. The resulting Cu-coated AC exhibited higher specific capacitance than that of AC under a high cycling rate of 100 C. This result suggests that Cu nanoparticles play an important role in enhancing the rate capability of AC. The improved cell performance might be attributed to the reduced charge transfer resistance between the Cu-coated AC electrode and organic electrolyte while maintaining surface stability.