LiCoPO_4包覆的Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2锂离子电池正极材料:增强的库伦效率和循环性能

LiCoPO_4-coated Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2 as a cathode material with improved columbic efficiency and cyclability for Li-ion batteries

LiCoPO_4包覆的Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2富锂正极材料是通过沉淀法制备的。包覆后的样品的首次库伦效率达到84.14%,在0.1C(1C=300mA/g)电流下放电比容量高达305.95mAh/g。特别是包覆后样品的循环性能得到极大的提升,1C倍率下100次循环后容量保持率为88.2%,远远高于未包覆样品的72.3%。这些电化学性能的提高主要归功于包覆层,包覆层不但增强了材料的结构稳定性,同时也有效保护了电极材料不受电解液的侵蚀并且提高了材料的锂离子迁移率。

LiCoPO4 coated Li1.2Mn0.54Ni0.13Co0.13O2 cathode materials were prepared by the precipitation method. The coated sample demonstrates high initial columbic efficiency of 84. 14% and a large reversible capacity of 305. 95 mAh/g at 0. 1 C （1 C =300 mA/g）. Especially,the coated sample demonstrates a better cycling per-formance, with capacity retention of 88. 2% at 1C rate after 100 cycles,which is much better than that of 72. 3% in the pristine sample. The improved electrochemical properties have been ascribed to the LiCoP0 4 coating layer,which not only stabilizes the cathode structure, but also protects the Li-rich cathode material from side reaction with the electrolyte and increases the Li＋ migration rate at the cathode interface.