Reduction Of Graphene Oxide And Application In Activated Carbon Electrode Of The Supercapacitor

The electrochemical double layer capacitor is a new type of energy storage devicebetween conventional capacitor and lithium ion secondary battery, having high powerdensity than the lithium-ion battery, excellent cycle property, has been wide-spreadconcern in the field of electrochemical energy storage. Activated carbon is consideredto has bright industrial prospects for the electric double layer capacitor material due toa wide variety of sources, low cost, and stabile electrochemical properties, but theactivated carbon containing SP3hybridized carbon atom, result relatively low electronmobility. Therefore, in order to increase the conductivity of electrode material has toadd acetylene black as conductive agent in electric double layer capacitor electrodepreparation process. Graphene is a novel carbon material, carbon atoms arrange d in atwo-dimensional plane reticular structure up, having a high conductivity and a highelectron mobility been widely studied in the field of electrochemistry. This study addgraphene to AC to improve the electrode electrochemical performance.This paper use graphite oxide as raw material, using NaBH4chemical reductionand protection of nitrogen thermal reduction to prepare graphene, studied the differentof reductant content and reduction temperature on the reduction of graphene surfacearea, structure and morphology; Graphene add to AC by dry and wet method，usingconstant current charge and discharge, cyclic voltammetry and electrochemicalimpedance to study the electrochemical behavior of the AC added graphene electrodematerial.Structural analysis showed that the graphene reduced using sodium borohydride(NaBH4-rGO) is obvious folds morphology, with the increase of the reducing agent,NaBH4-rGO sheet becomes gradually smaller, the aggregation of NaBH4-rGO becamemore obvious, morphology becomes irregular,the materials interlayer distance reducedfrom GO’s0.822nm to NaBH4-rGO-12’s0.358nm. Graphene prepared by thermalreduction also present flake morphology， as the thermal reduction temperatureincreased the TRGO peeling layers becomes large extent and the interlayer distancereduced from GO’s0.822nm to TRGO-600’s0.336nm.Charge-discharge tests show that added graphene to AC can increase the specificcapacitance of the materials in inorganic electrolyte and organic electrolyte, thespecific capacitance of134.6F/g at the current density of1mA/cm2is obtained inorganic electrolyte with5wt%content of TRGO-500in AC, improve18%than the adding acetylene black AC electrode(114.1F/g), the specific capacitance of ACelectrodes using dry method to add5wt%NaBH4-rGO in organic electrolyte is143.8F/g, improve26%than the adding acetylene black AC electrode; At the current densityof8mA/cm2, the specific capacitance of AC-rGO-2-1is194.3F/g in organic electrolyte,21%higher than the specific capacitance of AC electrode(160.6F/g), when the currentdensity incresed to20mA/cm2, the specific capacitance of AC-rGO-2-1is190.8F/g,19.1%higher than the specific capacitance of AC electrode(160.0F/g).