Synthesis of Fe.sub.2O.sub.3-Ni.sub.2/graphene nanocomposite by one-step hydrothermal method for high-performance supercapacitor

Graphene-based nanocomposites have been one of the most attractive electrode materials of supercapacitors. But in most cases, graphene-based nanocomposites always use single nanoparticle as active material, which cannot meet the increasing demand for next generation of energy storage devices. In the present paper, we prepared Fe.sub.2O.sub.3-Ni(OH).sub.2/graphene nanocomposite by simple one-step hydrothermal method. The dual-particle system reveals a synergistic effect between Fe.sub.2O.sub.3 and Ni(OH).sub.2, i.e., Ni(OH).sub.2 can enhance the electrical conductivity of Fe.sub.2O.sub.3, and then Fe.sub.2O.sub.3 can act as electrical conductivity bridges between Ni(OH).sub.2 nanoparticles and RG. As a result, the Fe.sub.2O.sub.3-Ni(OH).sub.2/graphene nanocomposite presents impressing electrochemical performance, including high specific capacitance (~857 F/g), good rate capability, and outstanding cycling stability (after 5000 cycles, 100 % retention).