锂离子电池富镍正极材料表面化学及改性研究

Surface Chemistry and Modification on Ni-rich LiNi_(1-x)M_xO_2 Cathode Materials for Li-ion Batteries

锂离子电池富镍系正极材料LiNi_(1-x)M_xO_2(1-x>0.6;M=Co、Mn、Al等)具有高容量、低成本而被认为是最有希望的候选者。尽管如此,富镍系正极材料容易吸收空气中的CO_2和H_2O发生副反应生成Li_2CO_3和LiOH杂质,生成的杂质和电解液发生反应在材料表面形成绝缘层;同时Ni^(2+)容易从过渡金属层迁移到锂层,造成离子混排;高活性Ni^(4+)也会加速电解液分解,导致电解液耗尽。本文首先介绍了富镍系正极材料的表面化学,然后总结了目前的改性方法,以改善其电化学性能和减少过渡金属溶解。

Ni-rich Li Ni1-xMxO2 （ 1 -x 〉0. 6, M = Co, Mn, A1, etc） cathode materials of Li-ion batteries areconsidered to be the most promising candidates because of their high capacity and low cost. However, Ni-rich cathodeseasily absorb the CO2 and H20 in air forming Li2CO3 and LiOH, these residual species can react with electrolyte forminginsulating materials on the surface of the electrode. In addition, Ni2. ions easily migrate from the transition metal layer tothe lithium layer, resulting in the cation mixing＇ highly reactive Ni4 can accelerate electrolyte decomposition, leading toelectrolyte depletion. The surface chemistry of LiNit_x Mx 02 materials were introduced, the methods of modification of Li Ni1-xMxO2 at present were summarized, to not only improvedissolution of transition metals.its electrochemical performance, but also moderate the