Room-temperature synthesis of sponge-like Co/Co(OH)2 nanocomposite for high-performance electrochemical Capacitors

In order to reduce the cost of electrode active material, a three-dimensional (3D) sponge-like Co/Co(OH) 2 nanocomposite was synthesized by a simple NaBH 4 reduction method at room temperature. For supercapacitor application, the Co/Co(OH) 2 nanocomposite exhibits an excellent specific capacity of 1048 F g −1 at a current density of 1 A g −1 in a potential range of 0–0.45 V from the charge/discharge test, and the retention of capacitance is 70.6% after 5000 cycles. The sponge-like Co/Co(OH) 2 nanocomposite displays high supercapacitor performance, excellent rate capability and cycling stability.