碳酸盐共沉淀法制备LiNi0.5Co0.3Mn0.2O2及其性能

以化学共沉淀法制备出的球形Ni0.5Co0.3Mn0.2CO3前驱体,合成了振实密度高达2.60 g/cm3的球形正极材料LiNi0.5Co0.3Mn0.2O2.研究表明,LiNi0.5Co0.3Mn0.2O2为10 μm左右的球形粉体,为纯相的α-NaFeO2层状结构.在2.7～4.3V,0.2 C倍率进行充放电,LiNi0.5Co0.3Mn0.2O2的首次放电比容量170.2 mAh/g,50次循环后容量保持率为94.3%;在2.7～4.6 V,在0.2 C倍率下放电,首次放电比容量为191.8 mAh/g,循环50次后容量保持率为90.5%.LiNi0.5Co0.3Mn0.2O2的首次循环伏安测试结果和交流阻抗测试结果进一步表明材料具有良好的电化学性能.

Synthesis and characterization of high-density spherical LiNi0.5Co0.3Mn0.2O2 by carbonate coprecipitating

Spherical LiNi_(0.5)CO_(0.3)Mn_(0.2)O_2 powders whose tap-density can reach 2.60 g/cm~3were synthesized from the coprecipitated carbonate precursor Ni_(0.5)Co_(0.3)Mn_(0.2)CO_3. The results showed that LiNi_(0.5)Co_(0.3)Mn_(0.2)O_2 were spherical powders which sizes were approximately 10 μrn, and all LiNi_(0.5)Co_(0.3)Mn_(0.2)O_2 materials were pure phase with layered structure. Spherical LiNi_(0.5)Co_(0.3)Mn_(0.2)O_2 delivered 170.2 and 191.8 mAh/g at the rate of 0.2 C at the voltage range of 2.7～4.3 V and 2.7～4.6 V in the first cycle, and the capacity retaining ratios were 94.3% and 90.5% after 50 cycles respctively. The results of CV and AC impedance furtherly showed that spherical LiNi_(0.5)Co_(0.3)Mn_(0.2)O_2 presented excellent electrochemical performance.