Study On Construction Of Mo-Co-Ni Based Nanoarrays Flexible Electrodes And Their Electrochemical Properties

Supercapacitors are one of the most potential energy storage devices,and are expected to solve the storage problems of new energy and renewable energy.However,there are still some problems such as low conductivity,unsatisfactory specific capacity and the rigidity of electrode,which hinders its large-scale application.Supercapacitor electrode with high capacitance mainly bases on the careful design of nanostructures and the intelligent hybridization of custom active materials.In this paper,a series of nano-array electrodes were prepared and their electrochemical performance was studied.In situ growth of Mo-Co-Ni trimetallic nanowire arrays on carbon cloth have been fabricated by a bracket-hydrothermal method.At the same time,the bracket was designed to assist hydrothermal reaction and solve the problem of uneven growth of nanoarrays prepared by ordinary hydrothermal methods.The morphology of nanowire arrays synthesized in different hydrothermal temperature and time are analyzed.The electrochemical performance of the synthesized electrdes was tested with a three electrode system.The test results showed that Mo-Co-Ni trimetallic nanowire arrays prepared at a hydrothermal temperature of 100? for 12 h own the highest specific capacity.Mo-Co-Ni trimetallic nanowire arrays exhibit areal capacitance of 2.10F·cm^-2 at the current densities of 1 mA cm^-2,and maintain 85.4%of the highest value after 3000 cycles.The Mo-Co-Ni nanowire arrays were vulcanized by a hydrothermal method to obtain the trimetal sulfide nanotube arrays.The electrodes synthesized in different sulfur sources,vulcanization temperature,time and the concentration of sulfur source are electrochemically tested for comparison.The results showed that the specific capacity of the sulfide nanotube arrays obtained under the optimal conditions was significantly improved compared with the precursor nanowire arrays.Sulfide nanotube arrays exhibit areal capacitance of 2.52 F·cm^-2 at the current densities of 1mA cm^-2,and achieve long cycle stability retaining 89.1%after 3000 cycles.The Ni-Co nanosheet arrays were directly supported on the carbon cloth via an easy-controlled electrodeposition method.The areal capacitance of the electrode is4.32 F·cm^-2 at the current densities of 1mA cm^-2,and maintains 75.1%of the highest value after 3000 cycles.A novel 3D Mo-Co-Ni(nanotube)@Ni-Co(nanosheet)core-shell arrays were prepared via bracket-hydrothermal method and electrodeposition method.The results showed that the 3D core-shell nanoforest arrays with electrodeposition of 180 s have the best electrochemical performance.Due to its unique hierarchical structure and the synergy of multiple components,it has superior electrochemical performance than single nanowire arrays,nanotube arrays,and nanosheet arrays.The 3D core-shell nanoforest arrays electrode shows outstanding electrochemical activity:a superb areal capacitance of 9.81 F cm^-2(1998.0 F g^-1)at the current densities of 1 mA cm^-2,as well as long cycle stability(after 3000 cycles maintains 85.4%of the highest capacitance value).In addition,it is worth noting that the area capacitance of the 3D core-shell electrode is higher than the sum capacitance of nanotubes and nanosheets,indicating that the preparation of the hierarchical nanoarray structure can help to increase the loading of active materials and improve the electrochemical performance of the electrode.