Preparation And Application On All-solid-state Flexible Supercapacitor Of Vanadium-based Nanocomposites

With the rapid development of portable energy storage devices,people are committed to the development of high-performance energy storage devices.In the past few decades,supercapacitors have made great progress of their attractive characteristics such as fast recharging,high power density,environmental friendliness and long cycle.The specific capacity and voltage window of electrode materials have great influence on the energy storage characteristics of supercapacitors.Therefore,the development of electrode materials with high specific capacity and large voltage window is the key to the development of energy storage technology.In this paper,two novel vanadium-based transition metal compound electrode materials are prepared for vanadium-based Nanocomposites as the research object,and their structure characterization and performance testing are carried out,as follows:Two-dimensional layered vanadium sulfide（VS₂）nanometer array are prepared through a hydrothermal method.The 1T-VS₂ grows on carbon cloth with high electrical conductivity.the three-dimensional open structure can provide high ion diffusion and electron transfer.Under the current density of 1 A/g,the capacity of VS₂ is 101 F/g.At the current density of 5 A/g,the capacity retention rate is as high as 98.8%after 1000 cycles,compared with pure VS₂ powder electrode,the specific capacitance and cycle performance of VS₂ arrays have obvious improvement.Based on VS₂ nanostructure arrays,a vanadium nitride/poly（3,4-ethylenedioxythiophene）（VN/PEDOT）mesoporous nanometer array are prepared by a high temperature nitriding process and rapid electro-deposition method.In 1M KOH the specific capacity of VN/PEDOT is 226.2 F/g.Through electrochemical dynamics calculation,constraint capacitance contribution is as high as 88.4%under the scanning rate of 5 m V/s.It should be noted that the electrode material maintains a circulation capacity of 91.5%for 5000 cycles at the current density of 10 A/g.In this design,the PEDOT composite enhances the specific capacity of the material while also enhancing its circulation stability.In order to explore the practicability of VN/PEDOT,VN/PEDOT and nickel-cobalt-aluminum oxide（NCA）were assembled into asymmetric flexible all-solid-state super-capacitor（VN/PEDOT//NCA ASC）in this paper.VN/PEDOT electrode widens the voltage window of the device,and NCA contributes high specific capacity to the super-capacitor.The device has 1.6 V voltage window and the device energy density can reach 48.36 Wh/kg（1.6 k W/kg）.And at the current density of 15 A/g,the capacity can still maintain 91.6%after 10000 cycles.This kind of flexible energy storage device based on vanadium nanomaterial provides a reference to the development of high-performance flexible energy storage.