汽车锂电池正极材料的制备与性能研究

研究了钼掺杂对汽车锂电池正极材料Mn_0.58Ni_0.18Co_0.14]_0.8-xMo_x（OH）₂物相组成、微结构和电化学性能的影响。结果表明,x=0.005的正极材料由于具有最强的超晶格结构稳定性而表现出最强的超晶格衍射峰,而x=0.01和x=0.02的正极材料中钼酸锂杂相峰的存在会一定程度上破坏超晶格结构;不同钼掺杂的正极材料的颗粒粒径会随着Mo含量增加而不断增大;钼掺杂可以提升正极材料的锂离子键入能力而消除非晶态碳酸锂薄层的影响,但是过量钼掺杂会形成钼酸锂化合物;x=0.005的正极材料的放电比容量最高、传荷阻抗最小,充放电过程中锂离子更容易嵌入脱出,从而具有较高的高倍率放电性能,这主要与此时颗粒粒径较小以及形成了纯层状结构有助于增强锂离子导电性和动力学反应速度有关。

Study on preparation and properties of cathode materials for vehicle lithium battery

The effects of Mo doping on the phase composition,microstructure and electrochemical properties of cathode materialMn_0.58Ni_0.18Co_0.14]_0.8-xMo_x（OH）₂ for vehicle lithium batteries were studied.The results showed that the x=0.005 ca-thode material exhibits the strongest superlattice diffraction peak due to the strongest superlattice structure stability,while the existence of Li₂MoO₄ heterophase peak in the x=0.01 and x=0.02 cathode materials will destroy the superlattice structure to a certain extent;the particle size of the cathode materials with different Mo doping will increase with the increase of Mo content;Mo doping can improve the Li separation of the positive materials and it can eliminate the influence of amorphous Li₂CO₃ thin layer by sub keying ability,but excessive Mo doping will form Li₂MoO₄ compound; x=0.005 cathode material has the highest discharge specific capacity and the smallest charge transfer impedance,and Li ion is easily embedded and detached more during charging and discharging,so it has high power discharge performance.It is mainly related to the smaller particle size and the formation of pure layered structure,which is helpful to enhance the conductivity of lithium ion and kinetic the reaction rate of lithium ion.