Preparation And Electrochemical Performance Of Copper-doped Nickel-Cobalt Hydroxide One-Dimensional Flexible Electrode

Recently,flexible energy storage devices have attracted widespread attention in the field of portable and wearable electronic devices.Supercapacitors are considered to be a reliable power source due to their high-power density,fast charge and discharge rate and long cycling life.Compared with planar supercapacitors,the fiber shape design is easier to adapt to complex deformation such as bending,torsion,stretching,etc.,therefore more suitable for flexible devices.However,the limited surface area of conventional fiber structures and the limitation of the reaction kinetics of active materials are detrimental to the practical applications of fiber supercapacitors.Therefore,achieving the controllable preparation of active materials with high mass loading on fiber-based current collectors,while solving their reaction kinetics,achieving high electrochemical performance and maintaining ultra-high cycling stability has to be settled urgently.Herein,an efficient multicomponent hierarchical structure by integrating the Cu-doped CoCu@NiCo-LDH core-shell nanowire arrays（NWAs）on the Cu fiber with highly conductive Au-modified CuO nanosheets is constructed（CoCu@NiCo-LDH NWAs@Au-CuO/Cu）via a novel in-situ corrosion growth method.In addition,this research work further studied the synergistic effect between CoCu@NiCo-LDH NWAs and Au-CuO nanosheet array,revealing the material hierarchical structure construction and electrochemical performance enhancement mechanism.The specific research contents are as follows:（1）Preparation and electrochemical performance of CoCu@NiCo-LDH NWAs@Au-CuO/Cu fiber electrode.The multicomponent hierarchical Cu-doped CoCu@NiCo-LDH NWAs@Au-CuO/Cu fibers were fabricated via alkaline oxidative etchant solution（AOES）based dipping method and zeolitic imidazolate framework（ZIF）derived three-step reaction.The large surface area is provided by multicomponent hierarchical structure,leading to the permeability of electrolyte solution.Furthermore,the electronic transmission is promoted by Cu dopants.Benefiting from the 3D multicomponent hierarchical structure and Cu dopants,effective ion diffusion and electron transport are promoted,and electrochemical reaction kinetics of the electrode is facilitated.Therefore,the fabricated electrode exhibits a high specific capacitance of 1.97 F cm^-2 and retains 79.2%with the current increased by 15 times.Moreover,the hierarchical structured fiber electrode shows a high capacitance retention of 90.8%after 30000 cycles,indicating its excellent cycling stability.（2）Electrochemical performance of CoCu@NiCo-LDH NWAs@Au-CuO/Cu//VN/carbon fibers hybrid supercapacitor.A flexible hybrid fiber SC is assembled with Cu-doped CoCu@NiCo-LDH NWAs@Au-CuO/Cu as a cathode and VN/carbon fibers as an anode,which achieves a remarkable maximal energy density of 34.97 Wh kg^-1 and power density of 13.86 kW kg^-1.Moreover,the hybrid fiber SC exhibits a superior cycling stability with 94.6%capacitance retention after 10000 cycles at 20 A g^-1.The unique multicomponent hierarchical structure exhibits a great potential in high-performance fiber shape energy-related systems.