Synthesis Of Tungsten Disulfide-based Composite Nanowires And Their Performance In Supercapacitors

In recent years,for the energy crises,environmental problems,the emergence of electrical vehicles and various portable electronic devices,the exploration of clean and renewable energy materials and energy storage equipment is urgent.The supercapacitor,as a new type of energy storage device,has many advantages,such as fast charging and discharging under high current density,high power density and long cycle life.It has been applied in electric vehicle power,rail train,aerospace,electronics,data memory storage systems and so on.Therefore,the research on electrode materials for supercapacitor has received great attention.Due to their unique physicochemical properties,graphene and graphite-like layered transition metal disulfides?TMDCs?show great potential as new energy materials.WS₂,as an important member of TMDCs,possess a large specific surface area and a layer spacing of 0.62 nm.These inherent structural features facilitate the rapid adsorption and transport of electrolyte ions,thereby increasing the rate performance of the energy storage device.Based on these advantages,WS₂ has aroused people's research interest as an electrode material for supercapacitors.However,WS₂ still faces low conductivity and stacking problems during electrochemical reaction when it is used as a electrode material for supercapacitors,which cause the research on WS₂ as the electrode material for supercapacitor Impeded.To overcome these issues,designing nanomaterials with mesoporous structure and compounding with high conductivity materials is an effective way to improve the performance of WS₂ electrode materials.In this work,the WS₂ nanowires with three-dimensional?3D?structure were prepared by electrospinning method,and Ni?OH?₂/WS₂ nanowires with 3D structure were successfully prepared by hydrothermal method.Then the electrochemical performance of the WS₂ nanowires and Ni?OH?₂/WS₂ composite nanowires as electrode materials for supercapacitors were studied.The research contents are listed as follows:?1?By electrospinning technology,using ammonium tetrathiotungstate?ATTT?and ammonium metatungstate?AMT?as precursor,two types of WS₂ nanowires with different morphology were successfully synthesized by one-step method and two-step method,respectively.The effect of calcination heating rate and vulcanization temperature on product morphology and purity were explored;?2?The WS₂ nanowires with 3D structure,which were prepared by the two-step method,were selected as the electrode material for the supercapacitor in the following study.The electrochemical performance of the WS₂ nanowire was tested in the three-electrode system.The test results show that the specific capacity of pure WS₂ nanowires is not ideal,and further compounding with other materials is needed to optimize the specific capacity and related electrochemical performance of WS₂-based composite nanowires;?3?Ni?OH?₂/WS₂ composite nanowires were prepared by a hydrothermal method,and the Ni?OH?₂/WS₂ composite nanowires maintained the original 3D morphology of the WS₂ nanowires.The specific surface area of the Ni?OH?₂/WS₂ composite nanowires is 64.563 m² g^-1.The electrochemical performance of Ni?OH?₂/WS₂composite nanowires was tested in a three-electrode system.Ni?OH?₂/WS₂ composite nanowires behaved a specific capacity of 354 C g^-1 at a current density of 1 A g^-1.When the current is increased from 1 A g^-1 to 10 A g^-1,the good rate performance was maintained and the electrode capacity retention rate is 68%;?4?The hybrid supercapacitor was prepared by using rGO as the negative electrode and Ni?OH?₂/WS₂ composite nanowires as the positive electrode.The electrochemical performance of the hybrid supercapacitor was tested.The hybrid supercapacitor behaved a high energy density of 34 Wh kg^-11 at the power density of980 W kg^-1.The capacity retention of this hybrid supercapacitor is 83%after 4000cycles at a current density of 4 A g^-1.