锂离子电池正极材料LiNi_(0.8)Co_(0.2)O_2的研究

低成本、高比容量的LiNi0.8Co0.2O2是取代已商品化锂电池正极材料LiCoO2的候选材料。用工业原料,通过共沉淀法(pH=11 2±0 05)合成了β Ni0.8Co0.2(OH)2,将其和LiOH·H2O混合,在空气中先后于650℃和750℃烧结8h和20h,制得具有良好层状结构的LiNi0.8Co0.2O2。用合成的材料制备电池,在0 2C、3 0～4 1V进行充放电实验,其放电平台在3 8V以上,首次放电容量超过170mA·h/g,10次循环后,放电容量还能保持在164mA·h/g左右,且库仑效率达到96%以上。

Study of LiNi0.8Co0.2O2 Cathode Material for Lithium Secondary Batteries

LiNi_(0.8)Co_(0.2)O_2 cathode material with both high specific capacity and low cost is a very promising candidate to replace the commercial LiCoO_2 for lithium secondary batteries.β-Ni_(0.8)Co_(0.2)(OH)_2 powders were prepared via a coprecipitation method (pH=11.2±0.05)using NiSO_4·6H_2O,CoSO_4·7H_2O,NH_3·H_2O and NaOH.LiNi_(0.8)Co_(0.2)O_2 powder with orderly layered structure was synthesized by sintering the β-Ni_(0.8)Co_(0.2)(OH)_2 and LiOH·H_2O in air atmosphere at 650 ℃ for 8 h,and after being ground,it was sintered again at 750 ℃ for 20 h.The voltage of the cells fabricated was over 3.8 V,and the first specific discharge capacity was over 170 mA·h/g.Its specific discharge capacity could still retain about 164 mA·h/g after 10 cycles at a 0.2 C rate between 3.0～ 4.1 V,and the coulombic efficiency was over 96%.