Preparation And Electrochemical Performance Of Co-Ni-V-O Solid Solution Anode Material

With the rapid development of new energy technologies such as wind energy and solar energy,the development of electrical energy storage technologies with higher power density and higher energy density is the current mainstream research and development direction.So far,graphite-based materials are commonly used as anode materials for lithium-ion batteries for commercial use,and its only theoretical capacity of 372 m A h g^-1 has gradually failed to meet its development requirements.The transition metal oxide cobalt vanadate material has achieved long service life,high electrochemical activity and excellent rate performance due to the high capacity of Co element and the stability of the VO_x amorphous array,which has attracted much attention.However,the disadvantages of cobalt vanadate materials,such as low electronic conductivity and large volume deformation,hinder its commercialization.In this context,this article starts from the intermetallic synergy mechanism,introduces Ni element through a variety of ways to modify the cobalt vanadate material,and successfully prepares Co-Ni-V-O solid solution materials with different structures.The two-dimensional porous Co-Ni-V-O solid solution material was successfully prepared by the 80?water bath reflux-atmospheric air sintering method.And carry on relevant characterization to it.The two-dimensional porous(Ni_xCo_1-x)₂V₂O₇ solid solution ultra-thin nanosheets prepared at a pyrolysis temperature of 400?and a molar ratio of cobalt and nickel materials of 4:1 have the best electrochemical performance.The reversible capacity was still maintained at 391 m A h g^-1 after 1500 cycles at a current density of 3 A g^-1,indicating that Ni elemental recombination can effectively improve the electrochemical performance of the material.The two-dimensional nanosheet precursor was prepared by the 80?water bath reflow method,and then the Co/Ni/(Ni_xCo_1-x)₂VO₄ composite material with the unique2D-2D structure was successfully prepared by the in-situ topology conversion method,and related characterization was performed.Compared with before compounding,the electrochemical performance of Co Ni VO-3-400 and Co Ni VO-4-400 is more prominent.The reversible capacity was maintained at 796 m A h g^-1 and 573 m A h g^-1 at a current density of 3 A g^-1 for 1200 cycles.This is due to the unique structure of 2D-2D and the combination of Ni,so that there are several nanometer gaps between the originally tightly stacked nanosheets,which increases the active sites for chemical reactions and accelerates the transport of lithium ions during electrochemical reactions.At the same time,the Co and Ni metal in the gap greatly increase the electronic conductivity of the material.