无人机用锂离子电池正极材料Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)的Mo^(6+)掺杂改性研究

Study on Mo^(6+) doping into Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2) as cathode materials for Li-ion batteries applied in unmanned aerial vehicles

采用碳酸盐共沉淀法和高温烧结工艺将一定量的Mo^(6+)掺杂到Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)正极材料中。利用XRD、SEM、EDS和恒流测试仪研究Mo^(6+)掺杂对Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)正极材料的晶体结构、微观形貌和电化学性能的影响。结果显示,Li_(1.20)Mn_(0.52)Ni_(0.13)Co_(0.13)Mo_(0.02)O_(2)表现出更低的阳离子混排和优异的电化学性能。经过Mo^(6+)掺杂后的正极,由于Li^(+)高速的迁移速率,使得首次不可逆容量损失降低,并展现出更好的高倍率性能和优异的循环稳定性。在0.5C倍率下循环100周后,Li_(1.20)Mn_(0.52)Ni_(0.13)Co_(0.13)Mo_(0.02)O_(2)的容量保持率达到92.2%,远远大于Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)的87.5%。另外,当放电倍率增大到5C时,Li_(1.2)0Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)的放电比容量要比Li_(1.20)Mn_(0.52)Ni_(0.13)Co_(0.13)Mo_(0.02)O_(2)低21.0 m A·h/g。因此,采用Mo^(6+)掺杂改性Li_(1.2)0Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)正极材料,可以有效提高锂电池的循环保持率和高倍率放电性能。

A certain content of Mo^(6+) was doped into the Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)cathode materials via using the carbonate coprecipitation method and high temperature calcination process.The influences of doping Mo^(6+) on crystal structure,morphology and electrochemical properties of the cathode materials were investigated by XRD,SEM,EDS and galvanostatic chargedischarge tests.The results showed that the Li_(1.20)Mn_(0.52)Ni_(0.13)Co_(0.13)Mo_(0.02)O_(2)exhibited lower cation mixing and excellent electrochemical properties.Due to the high migration rate of Li^(+),the first irreversible capacity loss of the Mo^(6+) doped cathode was reduced,which led to better high rate performance and excellent cycle stability.After 100 cycles at 0.5C,the capacity retention rate of Li_(1.20)Mn_(0.52)Ni_(0.13)Co_(0.13)Mo_(0.02)O_(2)was 92.2%,which was much higher than that of Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)(87.5%).In addition,when the discharge rate increased to 5C the discharge capacity of Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)was 21.0 m A·h/g lower than that of Li_(1.20)Mn_(0.52)Ni_(0.13)Co_(0.13)Mo_(0.02)O_(2).Therefore,using Mo^(6+)doping Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)cathode materials could effectively improve the cycle retention and high rate discharge performance of lithium-ion battery.