ZnO包覆LiNi1/3Co1/3Mn1/3O2的表面结构和电化学性能

在LiNi_1/3Co_1/3Mn_1/3O₂正极材料表面包覆ZnO，通过X射线衍射（XRD）和光电子能谱（XPS）分析包覆层对正极材料表面状态的改变，并考察了改性后材料的放电容量、首次不可逆容量等电化学性能变化. 结果表明：ZnO主要存在于材料表面并影响着材料表面组成和电化学性质，材料表面镍和锰的含量随着包覆量的增加而增大；400 ^oC热处理可使过渡金属与锌在材料表面形成复合氧化物，过渡金属的结合能增大；包覆2%（by mass，下同）的ZnO可有效抑制55 ^oC下充放电时3.6 V附近的不可逆反应，提高了材料的首次库仑效率；包覆2% ZnO的电池材料在55 ^oC/0.5C的放电比容量和循环寿命最佳.

Surface Structure and Electrochemical Performance of ZnO Coated LiNi1/3Co1/3Mn1/3O2

The surface of LiNi_1/3Co_1/3Mn_1/3O₂ particles were modified by ZnO. Surface structure and electrochemical properties of the coated materials were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical tests. The results show that a ZnO coating affects the surface composition of LiNi_1/3Co_1/3Mn_1/3O₂ particles. The surface contents of nickel and manganese increase with the amount of ZnO coating. ZnO can react with LiNi_1/3Co_1/3Mn_1/3O₂ and a complex oxide is formed during the heat-treatment at above 400 ^oC. The electrochemical studies suggest that a ZnO coating hinder the electrochemical reactions near 3.6 V for pristine sample. The initial columbic efficiency is significantly enhanced by coating LiNi_1/3Co_1/3Mn_1/3O₂ with 2% (by mass) ZnO, which delivers high discharge capacity and shows excellent capacity retention at 55 ^oC/0.5C.