Electrospinning Method To Prepare Lithium Vanadate For Lithium Ion Battery And Its Modification

In order to improve the electrochemical performance of the positive electrode material LiV₃O₈,the positive electrode material LiV₃O₈ was prepared by sol-gel method combined with electrospinning method,and the modification of doped Nb⁵⁺and graphene was further studied.The morphology and structure of the composites were characterized by X-ray diffractometry?XRD?,field emission scanning electron microscopy?FRSEM?and transmission electron microscopy?TEM?.The cyclic voltammetry?CV?,alternating current impedance?EIS?and Electrochemical performance testing techniques were used to study the electrochemical performance of composite cathode materials.According to the test characterization results,the following conclusions are obtained:For the preparation of LiV₃O₈ cathode material by electrospinning,after a large number of experimental conditions such as spinning parameters,calcination temperature and holding time,the best preparation of cathode material LiV₃O₈ by sol-gel method combined with electrospinning method was obtained.performance.The experimental results show that the performance of the lithium vanadate material prepared by the electrospinning method is much better than that of the sol-gel method.The positive electrode material LiV_3-xNb_xO₈ was synthesized by ion doping.It is a uniform short rod-like nanostructure with the same crystal structure as LiV₃O₈.There is no lattice change due to doping.The charge and discharge test shows the electrochemical performance of LiV_2.94Nb_0.06O₈.Preferably,E-LVON6 shows good capacity properties(400.7 mAh g^-1,288.4 mAh g^-1,213.4 mAh g^-1)at current densities of 0.1 C,1 C,and 5 C,respectively,at various currents.There is almost no attenuation in the density cycle,even in the ultra-high current density of 20 C,the capacity remains at 97.9 mAh g^-1 after 500 cycles.The EIS results show that after doping with Nb⁵⁺,the resistance of the material particles and particles is slightly reduced,and the diffusion resistance of lithium ions in the material is significantly reduced,which will facilitate the rapid insertion/extraction of lithium ions in the material.The high temperature graphene was synthesized by chemical stripping method,and the linear structure of GO-LiV₃O₈ cathode material was successfully prepared by sol-gel method and electrospinning method.Optimized doping performance was explored by different doping ratios.Among them,the charge-discharge test shows that E-LVOG1.5 has the best electrochemical performance.Under normal temperature,the first discharge specific capacity is 289 mAh g^-1 at 1 C current density,and 277.8 mAh g^-1 after 200 cycles.The capacity retention rate was 96.2%.Even at an ultra-high current density of 20 C,it remained at 138.2 mAh g^-1 after 500 cycles.EIS shows that the internal resistance of lithium ions in the material is significantly reduced after doping graphene,which indicates that graphene doping can effectively improve the cycle performance of materials under high current density.