Preparation Of Molybdenum Disulphide And Application In Hybrid Capacitors

Carbon material is widely used commercial lithium-ion battery anode material.However,its low discharge capacity and easy to grow lithium dendrite,can not satisfy the needs of high power,high energy,high capacity.Molybdenum disulfide is a graphene-like compound,its two-dimensional structure to facilitate the insertion and removal of lithium ions.At the same time,synthesis method of molybdenum disulfide is relatively simple.It is widely concerned as high capacity and material in energy storage devices.In this paper,the molybdenum disulfide was tested by physical characterization such as XRD,SEM,XPS etc.Cyclic voltammetry,AC impedance,galvanostatic charge-discharge,the molybdenum disulfide was analyzed from structure,morphology and electrochemical properties of molybdenum disulfide to study.The molybdenum disulfide was synthesized by hydrothermal treatmennt.The molybdenum disulfide with regular morphology was obtained by optimizing the process reaction conditions such as the ratio of sulfur source and molybdenum source,the use of additives,reaction temperature and time.The electrochemical test results showed that the specific capacity of the molybdenum disulfide electrode can reach 337mAhg^-1,the reserved specific capacity of 57mAhg^-1 after 1000 cycles at the current density of 1 A g-1,which is better than commercial carbon material.The increase of the specific capacity of the electrode due to the regular cube structure of molybdenum disulfide.The lamellar structure and large specific surface area are favorable for the full contact of the electrolyte with the electrode,reducing the internal resistance of the battery,improving the magnification performance and cycle performance.The activated carbon was used as anode material,molybdenum disulfide as cathode material and 1 mol L-1 Li PF6-PC as the organic electrolyte.The hybrid capacitor was assembled.The working voltage of Mo S2 / AC lithium ion hybrid capacitor is 0-3.4 V with a high power and energy density.and the capacity retention rate is good.Although molybdenum disulfide has regular morphology and relatively stable electrochemical performance,the battery cycle performance is gradually deteriorated as the cut off charge voltage increased.At high current density,the polarization increased and the capacity decayed faster.The molybdenum disulfide coated with N-doped carbon was prepared by calcined polypyrrole.The electrochemical performance was tested.The results showed that the specific capacity was increased and the cycle performance was enhanced.At a high current density of 1 A g-1,the capacity can still reach 230mAhg^-1 after 500 cycles.After 500 cycles,the reserved capacity of original molybdenum disulfide was only 65mAhg^-1.The N-doped carbon coating layer enhanced the electrical conductivity and structural stability of the material,which insured the excellent electrochemical properties.