Ni–Co Oxy-hydroxides Preparation And Their Properties As Electrode Material Of Supercapacitor

Super capacitor is a new type of energy storage devices between conventional capacitors and batteries. It has more battery advantages, not only large power density and high secondary energy density of conventional capacitor, but also charging speed, long life cycle. The performance of the super capacitor has direct relationship with electrode materials. This paper prepared cobalt acid nickel material based on cheap cobalt and nickel salt, and prepared cobalt acid nickel carbon（Ni Co₂O₄-C） nickel and cobalt acid nickel polyaniline carbon（NiCo₂O₄-PAnC） composite electrode materials based on activated carbon and polyaniline carbon（PAnC）.This paper studied the material structure and electrochemical properties by the physical and chemical test methods. The crystal structure, surface morphology and the capacitance characteristic of the prepared materials were studied by cyclic voltammetry, constant current charge and discharge and other electrochemical testing methods, X-ray diffraction, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and other property characterization.In this paper, cobalt acid nickel carbon（NiCo₂O₄-C） composite electrode materials was prepared by simple coprecipitation method. Then Discussed the optimum preparation conditions of composite electrode materials. The results showed that the sintering temperature has a big impact to the formation of the cobalt acid nickel and the morphology, cobalt acid nickel will form only at the temperature more than 250 ℃. At 250 ℃ the average particle size of NiCo₂O₄-C material is about 6.7 nm, when the temperature is higher than 250 ℃,the size increase with the temperature. The best preparation conditions of the NiCo₂O₄-C electrode materials as follows: under the temperature of 250 ℃ calcination 4 h, C and NiCo₂O₄ ratio of 1:1. 5, Ni and Co ratio of 3:1. Polyaniline carbon electrode materials were prepared by oxidation. The reaction temperature, the ratio of reactants, etc were studied. The optimum conditions of synthesis were : at 25 ℃, using SDS, C and PAnC ratio of 5:2. For NiCo₂O₄-PAnC composite electrode materials, the best proportion of polyaniline carbon and and cobalt acid nickel is 1:1.5, the electrochemical properties of NiCo₂O₄-PAnC prepared by this proportion is the best and the specific capacitance is 569.33 F·g-1.Compared the nickel oxide, cobalt oxide, NiCo₂O₄, NiCo₂O₄-C composite electrode materials and the performance of the electrode NiCo₂O₄-C prepared by cobalt acid nickel and active carbon. The results show that the surrounded area of the NiCo₂O₄-C composite electrode materials is the biggest by the cyclic voltammograms under the same condition, and it has the largest permittivity.Compared the electrochemical properties of three materials: PAnC, Ni Co₂O₄-C and NiCo₂O₄-PAnC. The results show that the NiCo₂O₄-PAnC has a better electrochemical performance than PAnC, NiCo₂O₄-C, therefore compared three materials NiCo₂O₄-PAnC is a better material as super capacitor electrode.