Study On The Preparation And Capacitance Properties Of Nickel Oxide Composites

Supercapacitors are one of the most promising technologies for electrochemical energy conversion and storage due to their high power density, long life cycle. Because of their low price, abundant resource, environmental friendly and high specific capacitance, transition metal oxides have been widely reported by researchers. In this paper, we have successfully prepared Ni-Cu and Ni-Co oxide materials. The microstructure and morphology of materials were investigated by XRD, SEM, TEM and BET measurements. The electrochemical properties have been evaluated by cyclic voltammetry(CV), galvanostatic charge-discharge, and electrochemical impedance spectra (EIS). The main contents are the following:1. NiO-CuO composite was successfully synthesized by a facile chemical coprecipitation method. It has been found that the composite was constituted by the microsphere. The specific area of the composite reached to as high as132m2/g. By electrochemical tests, A maximum capacitance value of735F/g at a current density of lA/g was achieved, much higher than that of NiO (351F/g) and CuO (262F/g), respectively. In the charge/discharge process at a current density of lA/g, the composite (350℃) electrode could maintain98.2%of the initial specific capacitance after580cycles.2.Ni-Cu oxide materials were successfully synthesized by solution method. The results show that nickel oxide are deposited on the surface of CuO. The composite was sphere and porous. By galvanostatic charge-discharge tests, A maximum capacitance value of1131F/g at a current density of1A/g was achieved, much higher than that of CuO (262F/g). In the charge/discharge process at a current density of1and16A/g, the composite electrode could maintain99.6%and100%of the initial specific capacitance after1000cycles, respectively, higher than that of CuO (92.3%). The electrochemical performance shows that the synergies between CuO and nickel oxide result in an increased specific capacitance and cycling stability. 3.Ni-Co oxide materials were prepared by solution method. The composite was constituted by one dimensional rods and granules. The specific area of the composite reached to70m2/g. By electrochemical tests, A maximum capacitance value of1112F/g at a current density of2A/g was achieved, much higher than that of Co3O4(360F/g). In the charge/discharge process at a current density of2A/g, the composite electrode could maintain97%of the initial specific capacitance after1000cycles, higher than that of Co3O4(95.9%). The electrochemical performance shows that the synergies between Co3O4and nickel oxide result in an increased specific capacitance and cycling stability.