Graphene/Nickel Oxide Hybrid And Its Application For Supercapacitor

Supercapacitor, as a new kind of charge-storage device, has high power density, long cycle life and the friendliness to environment. It shortens the gap between traditional capacitor and battery and is widely used in the field of transportation, electronic devices, and mobile communications. As the main part of supercapacitor, active material is the key factor in controlling of capacitive properties. Here, graphene is used as the matrix to form nano-scale nickel oxides for its outstanding characters like high surface area and good mobility of charge carry. In this context, three parts of work were discussed:1) Nano porous NiO is obtained by the assistance of eggshell membrane. The as-prepared NiO is composed of particles in5-10nm and owns good capacitive properties, showing a specific capacitance of550F·g-1at the current density of1A·g-1.2) The impact of oxygen functional groups on graphene is studied. The graphene oxide used in the experiment is prepared by Hummer method, and the graphene is obtained by chemical reduction of graphene oxide. Electrochemistry characterizations confirm that graphene shows better properties of charge transfer, attributing to less oxygen groups which are considered block in the process. And the capactive properties of graphene is better than graphene oxide (38F·g-1vs73·F·g-1)3) Reduced graphene oxide/NiO hybrid is obtained through a simple chemical deposition and following hydrothermal process. Graphene in hybrid can not only supply conductive network for NiO, but stop NiO nanoparticles from agglomeration. The hybrid shows a specific capacitance of570F·g-4(vs.285F·g-1of NiO prepared with same method) and75%remaining after1000cycle charge/discharge test.