Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_2的PVP凝胶燃烧法合成

Synthesis of cathode material Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_2 via a PVP gel-combustion method

采用聚乙烯吡咯烷酮(PVP)凝胶燃烧法合成了高容量的Li[Li0.2Mn0.54Ni0.13Co0.13]O2正极材料,研究其结构、形貌和电化学性能。X射线衍射光谱法(XRD)分析表明材料为典型的α-NaFeO2结构,R-3m空间群,结晶良好。从扫描电子显微镜(SEM)图可见材料的晶型发育良好,粒径均匀,大部分晶粒的粒径在0.1-0.2μm,平均粒径为0.16μm。材料在0.1 C下的首次充电比容量为351.5 mAh/g,放电比容量为284.3 mAh/g,库仑效率为80.9%。0.5 C和1 C的首次放电比容量分别为236.1和210.0 mAh/g,分别相当于0.1 C首次放电比容量的83.0%和73.9%。该材料在1 C下经过30次循环,容量保持率为85.3%。第2-30次充放电平均库仑效率为98.9%,具有良好的充放电可逆性。

Li-rich cathode material Li [Li0.2Mn0.54Ni0.13Co0.13]O2 with high capacity was synthesized via a PVP（polyvinylpyrrolidone） gel-combustion method.Its structure,morphology and electrochemical performance were studied.XRD analysis indicates that the material has a typical α-NaFeO2structure and R-3m space group,and the crystallinity is high.SEM image show that the material has good crystallinity and uniform particle size distribution.The size of most grain is 0.1-0.2 μm and the mean size is 0.16 μm.The first charge specific capacity,discharge specific capacity and coulombic efficiency of the material at 1 C（1 C = 250 mA/g） are 351.5,284.3 mAh/g and 80.9%,respectively.The first discharge specific capacities at 0.5 C and 1 C rates are 236.1 and 210.0 mAh/g,which correspond to 83.0% and 73.9% of the first discharge specific capacity at 0.1 C.The capacity retention after 30 cycles at 1 C is 85.3%.The material also has good charge and discharge reversibility for the average coulombic efficiency of the 2th-30thcycles is 98.9%.