Facile synthesis of 3D flower-like mesoporous Ni@C composite for high energy aqueous asymmetric supercapacitors.

A 3D flower-like mesoporous Ni@C composite material has been synthesized by using a facile and economical one-pot hydrothermal method. This unique 3D flower-like Ni@C composite, which exhibited a high surface area (522.4m(2)g(-1)), consisted of highly dispersed Ni nanoparticles on mesoporous carbon flakes. The effect of calcination temperature on the electrochemical performance of the Ni@C composite was systematically investigated. The optimized material (Ni@C700) displayed high specific capacity (1306Fg(-1) at 2Ag(-1)) and excellent cycling performance (96.7% retention after 5000cycles). Furthermore, an asymmetric supercapacitor (ASC) that contained Ni@C700 as cathode and mesoporous carbon (MC) as anode demonstrated high energy density (60.4Whkg(-1) at a power density of 750Wkg(-1)).