高容量富锂三元材料xLi_2MnO_3·(1-x)LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2的制备与性能研究

Preparation and property of high capacity Li-rich anode material xLi_2MnO_3·(1-x)LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2

以氢氧化物共沉淀法制备前驱体,碳酸锂(Li_2CO_3)为锂盐,高温烧结合成富锂正极材料锂镍钴锰复合材料[xLi_2MnO_3·(1-x)LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2(x=0.1,0.2,0.3,0.4,0.5)]。结构分析显示,所制材料都是由小晶粒团聚烧结形成的不规则二次颗粒组成,呈现典型的α-NaFeO_2结构。电性能研究表明,随着x值的增大,所制材料的层状结构趋于完善,且在高电压深度充电下的结构稳定性增加,电荷传递阻抗显著减小,电性能逐渐改善。Li1.167Ni0.433Mn0.3Co0.1O2(x=0.5)表现出了较小的电极极化和较快的电极-界面反应,电性能最佳,其0.1C初始放电容量达251.5mAh/g,在0.2C倍率条件下循环30次后容量保持率达86.9%。

Li-rich anode material xLi2MnO3·(1-x)LiNi0.6Co0.2Mn0.2O2(x=0.1,0.2,0.3,0.4,0.5)were synthesized by annealing the mixture of hydroxide precursors with Li2CO3.Structure analysis revealed that as-prepared materials presented irregular secondary particles morphology and typicalα-NaFeO2 layered phase structure.Electrochemical properties analysis showed that increasing Li2 MnO3 content value x leaded to improved layered structure,increased the structural stability at high charge voltage and deep charge state,decreased electron transfer resistant,and thus improved electrochemical performance.Li1.167 Ni0.433 Mn0.3 Co0.1 O2(x=0.5)with the lowest electron transfer resistant exhibited the best charge-discharge properties.Its initial discharge capacity at 0.1 C reached251.5 mAh/g,and the capacity retention remained 86.9%at 0.2 Cafter rate capability test for 30 cycles.