磷酸钒锂正极材料粒径控制与电化学性能研究

Particle size control and electrochemical properties of lithiumvanadium phosphate cathode materials

采用Li_(2)CO_(3)、V_(2)O_(5)、NH_(4)H_(2)PO_(4)为主要原料,以蔗糖、柠檬酸为混合碳源,无水乙醇为分散剂,经球磨制得前驱体,在N_(2)保护下高温烧制,得到碳包覆磷酸钒锂正极材料。进行了球磨时长与前驱体粒径对比、气氛烧制时长与目标材料粒径对比、目标材料粒径与电化学性能的对比研究。系列XRD、SEM、粒径表征以及比容量、循环和倍率等电化学测试表明,在一定球料比以及转速下,球磨时长9 h,前驱体粒径分布较理想;800℃气氛烧制时长16 h,目标材料粒径分布更理想,且材料的比容量、循环性能、倍率性能等综合电化学性能更好。

Using Li_(2)CO_(3),V_(2)O_(5),NH_(4)H_(2)PO_(4) as the main raw material,sucrose and citric acid as the carbon source,anhydrous ethanol as the dispersant,the precursor was obtained by ball grinding and drying.The high temperature roasting under N_(2) protection,and a series of pure phase carbon-coated vanadium-lithium phosphate cathode materials were prepared.And the ball milling time was compared with the particle size of the precursor,the comparison between the roasting time and the particle size and electrochemical properties of the target material,and the comparative study of the particle size of the precursor and the particle size of the target material.A series of XRD,SEM,particle size characterization and specific capacity,cycle and magnification electrochemical tests show that at a certain ball material ratio and rotational speed,the ball milling time is 9 h,and the precursor particle size distribution is ideal;the particle size of the target material with a calcination temperature of 800℃and a time of 16 h is smaller and the comprehensive electrochemical performance is better,such as specific capacity,cycle performance and rate performance.