Study On The Modification Of MoS₂ Of Electrode Material Of Supercapacitor

Energy shortage is a major global problem for humankind.Green and efficient supercapacitors stand out from many energy storage devices,among which transition metal sulfide is a research hotspot of electrode materials in recent years.MoS₂ being used as the matrix material.The electrochemical properties of MoS₂ is firstly improved by combining with PPY and doping with element Co,and then Mo_0.7Co_0.3S₂ with good pseudo capacitance is compounded with g-C₃N₄ and rGO respectively.The microstructure and electrochemical properties of the modified composites were studied.The main contents are as follows:1.Pure MoS₂ was prepared by hydrothermal method,and then pure PPY and MoS₂/PPY composite were prepared by in situ polymerization respectively.The materials were characterized by XRD?SEM?TEM and EDS techniques.The results show that the pure MoS₂being hexagonal system and pure phase with lamellar structure and flower-like microspheres.And the composite with 45%PPY ratio is microsphere-like,and the particle size is uniform,and the parts of each element are uniform.The specific capacitance of its electrode is 750 Fg^-1and 604.38 Fg^-11 before and after the scanning rate increased by 20 times,and the capacitance retention rate is 80.6%.2.Co-doped Mo_1-x-x Co_xS₂ electrode material was prepared by hydrothermal method.It is found that the sample of Mo_0.7Co_0.3S₂ is a flower-like microsphere structure.Each electrode shows pseudocapacitive behavior.When the scanning rate is 50mVs^-1,the specific capacitance of Mo_0.7Co_0.3S₂ electrode is the highest,which is 765.13 Fg^-1.Moreover,the impedance of Mo_0.7Co_0.3S₂ electrode is the smallest and the capacitance retention rate is the highest.3.g-C₃N₄ were prepared by high temperature sintering method,and Mo_0.7Co_0.3S₂ was grown uniformly on the surface of g-C₃N₄ by hydrothermal method,which synthesized the composite materials Mo_0.7Co_0.3S₂/g-C₃N₄.When the content of g-C₃N₄ is 10 wt.%,the specific capacity of Mo_0.7Co_0.3S₂/g-C₃N₄ electrode is the largest,and the capacitance retention rate is 86.28%after the scanning rate increases by 20 times.Graphite phase nitrogen carbide can effectively reduce its impedance,making the impedance of its electrode minimum.At current density of 5 Ag^-1,the charge energy storage efficiency is as high as 97.46%after3000 long cycle tests,showing excellent cyclic stability and capacitive behavior.4.GO was prepared by Hummers method,and then Mo_0.7Co_0.3S₂/rGO nanocomposites with different rGO contents were prepared by hydrothermal method,which appeared to be a flower shaped microsphere similar to MoS₂,coated with a Gossamer graphene layer.When the rGO content is 10 wt.%,the capacitance performance of the Mo_0.7Co_0.3S₂/rGO electrode material is the best,and the specific capacity is 1648.75 Fg^-11 and 1386.06 Fg^-11 at 5 mVs^-11 and100 mVs^-1,and the capacitance retention is 86.47%.rGO optimizes the conductivity of the electrode material,showing the best conductivity its electrode.