The Research Of Molybdenum Based Supercapacitor Electrode Materials Preparation And Electrochemical Proformance

Due to the traditional fossil fuel consumption and petroleum resource shortage, and the environmental problems caused by the burning of fossil fuels, in the next few years nonrenewable resources use will greatly down. To select renewable energy and the development of environmentally friendly new energy conversion and storage devices is very important. Supercapacitor as an intermediate between conventional capacitors and lithium-ion battery new energy conversion and storage equipment, has the advantages of rapid charge discharge, long cycle life, abundant raw materials, no pollution to the environment, has been caused widespread concern and research, the key factor that affeccts the electrochemical performance of the supercapacitor is electrode material.The molybdenum based electrode material has the advantages of special structure, rich raw materials, high theory specific capacitance, easy preparation, no pollution to the environment, and so on, but the poor cycle performance and the specific capacitance is less than the theoretical values. This paper mainly to improve the specific capacitance as the starting point, Co3O₄、NiMoO₄ and FeS₂ as the object of study, by doping with metal composite, the molybdenum based composite electrode materials were prepared. The morphology and microstructure were analyzed by means of XRD and SEM characterization, by cyclic voltammetry, AC impedance, constant current charge discharge test method examines the electrochemical performance of the composite electrode materials and for development of molybdenum based electrode materials for the beneficial exploration. The main research contents are as follows:（1） By hydrothermal method to prepare Co3O₄ electrode materials, and Co3O₄@MoO2 nanocomposites were prepared by electrochemical deposition method on Co3O₄. Electrochemical measurements show that the specific capacitance of the Co3O₄@MoO2 nanocomposite is larger than that of the single MoO2 and Co3O₄. The AC impedance plots show that MoO2 and Co3O₄ formed composite materials, the conductivity is greatly improved and the internal resistance is reduced. Cycle performance tests show that Co3O₄@MoO2 after 1000 cycles capacitance can still maintain to 83% of the original capacitance. The paper also investigated under different current on the electrochemical properties of the prepared Co3O₄@MoO2 nanocomposites and the effect of Al doping on the electrochemical properties of the prepared Co3O₄@MoO2 nanocomposites.（2） NiMoO₄ nanomaterial were prepared by hydrothermal method, and the NiMoO₄@Ni（OH）₂ nanocomposites were successfully prepared by electrochemical deposition method on NiMoO₄. First, the electrochemical performance of NiMoO₄ with different hydrothermal time was investigated, and it was concluded that the best electrochemical performance of NiMoO₄ prepared by hydrothermal time was 1 h, which was obtained by electrochemical test. The electrochemical properties of NiMoO₄@Ni（OH）₂ nanocomposites obtained by different electrodeposition time were also investigated, and the composite materials were obtained by the deposition time is 30 min with high specific capacitance, and the capacitance is higher than single NiMoO₄ nanomaterial. Cycle performance test shows that NiMoO₄@Ni（OH）₂ after 200 cycles capacitance can still be maintained to the original 64%. NiMoO₄@NiO nanocomposites were obtained by calcination of NiMoO₄@Ni（OH）₂, electrochemical tests show that the capacitance of NiMoO₄@NiO is higher than that of pure NiMoO₄.（3） Few works have been reported on the supercapacity of FeS₂, the hydrothermal method was successfully prepared Mo-doped FeS₂ nanocomposite, by changing the reaction temperature, reaction time, reactant ratio were prepared with different morphologies and properties Mo-doped FeS₂. The electrochemical performance of Mo-doped FeS₂ was better when the hydrothermal reaction conditions were 160 ℃ and 24 h, at the same time FeSO₄·7H2O and NiMoO₄·4H2O the molar ratio of was 10:3 was obtained by electrochemical test. The highest Mo-doped FeS₂ capacitance was 542.5 F g-1, which was higher than that of pure FeS₂（322.14 F g-1）.