Study On Electrochemical Hybrid Capacitor Of Graphene / MoO Graphene Organic System

The electrode material of Electrochemical hybrid capacitors in organic electrolyte usually uses capacitor electrode material and the material using for lithium-ion batteries. Electrochemical hybrid capacitors in organic electrolyte combines high energy density and power density, making the capacitor applications more widely. In the charge-discharge process in order to improve the performance of the hybrid capacitor requires a very good match between positive and negative owing to the two different materials as electerode in hybrid capacitor. So, The reaserch on the electrode materials and the match between negative and anode eletrode materials is the focus of hybrid capacitors.In this paper, graphene-MoO2was prepared by reduction of graphene oxide-MoO2Synthesized by the method of self-assembly and its physical structure was characterized by means of XRD, TEM. The electrochemical performance was analyzed by galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectra in detail. In addition, the hybrid capacitors in organic electrolyte consisting of a graphene cathode and an graphene-MoO2anode were fabricated and its performance was studied. The main conclusions are given as follows.1. Gaphene-MoO2composite were developed via reduction of graphene oxide-MoO2Synthesized by the method of self-assembly. The materials with different proportion were obtained by changing the amount of gaphene. The redox process of the gaphene-MoO2composite were obviously observed by cyclic voltammetry(CV) tests in1M LiPF6. The composite prepared in11mg gaphene exhibits the highest specific capacitance of1089.7mAh·g-1at a current density of0.1A·g-1during the galvanostatic charge-discharge measurements and it still retain a capacity of204mAh·g-1at2A·g-1. It is obviously that the material owns the high power density.2. The hybrid capacitor based on grahene cathode and GP-11anode was assembled. The mass ratio of anode to cathode was optimized. The experimental results revealed that Hybrid capacitors have the right ratio of energy density and power density when mass ratio mGp/mMoO2-GP was3.6±0.1. Then the performance of the hybrid capacitor was optimized on the basis of explorations of the factors affecting hybrid capacitor performance.The experimental results revealed that the capacitance of the hybrid capacitor reached55.2mAh·g-1at the current density of0.5A·g-1when mass ratio mGp/mMoO2·GP was1and the voltage range was0.7-4.7V and it delivers an energy density of55.2mAh·g-1in1M LiPF6at a power of532W·kg-1, which is much higher than that of symmetric capacitor of14.5Wh·kg-1at a power density of72.5W·kg-1at0.5A·g-1.