Synthesis And Performance Of High Nickel Cobalt-Free Cathode Materials For Lithium-Ion Batteries

With the development of modern electric vehicles,the energy storage of batteries has attracted much attention.The specific capacity of traditional lithium-ion batteries has not met the needs of modern electric vehicles,and higher energy storage batteries have become an important part of new hybrid vehicles.High nickel cobalt-free cathode materials have attracted much attention due to their high capacity density,environmental friendliness and low price,and have become a research hotspot of cathode materials.However,while saving costs,it is also accompanied by problems such as poor cycle stability and thermal stability.In order to overcome these difficulties,this paper proposes an experimental scheme to improve the electrochemical performance of cathode materials for lithium-ion batteries.In this paper,Li Ni_xMn_1-xO₂（LNMO）was used as the research object,and high nickel cobalt-free cathode materials were synthesized by electrospinning and hydrothermal methods.The electrochemical performance of LNMO cathode material was improved by optimizing the synthesis process and ion doping modification of the material,which also laid a certain foundation for the development of high nickel cobalt-free cathode materials.1.Nanofibrous Li Ni_0.8Mn_0.2O₂ cathode material was synthesized by electrospinning.When the curing distance is 15 cm,the voltage is 14 k V and the PVP content in the spinning solution is 15%,the electrode material has the best electrochemical performance.At a current density of 0.1 C and a voltage window of 3.0-4.3 V,the initial discharge specific capacity is90.3 m Ah g^-1,and the capacity retention rate is 99.2%after 100 charge-discharge cycles.2.Spherical Li Ni_xMn_1-xO₂（LNMO）cathode materials were synthesized by hydrothermal method.When x=0.30 and the hydrothermal reaction temperature is 180°C,the prepared electrode material has the best electrochemical performance.3.Zr-doped Li Ni_0.7Mn_0.3-xZr_xO₂（NMZ）cathode material was synthesized by hydrothermal method.When x=0.02 and the excess amount of lithium is 5%,the prepared electrode material still has a discharge specific capacity of 129.5 m Ah g^-1 and a capacity retention rate of 83.5%after 100 cycles at a current density of 0.1 C.4.Mg-doped Li Ni_0.7Mn_0.3-xMg_xO₂（NMMg）cathode material was synthesized by hydrothermal method.When x=0.02 and calcined at 800°C,the electrode material still has a discharge specific capacity of 130.2 m Ah g^-1 and a capacity retention rate of 76.6%after 100charge-discharge cycles at a current density of 0.1 C.