Effect of lithium to zirconium ratio on microstructure and electrochemical performances of LZO modified LiNi0.8Co0.1Mn0.1O2 cathode materials

被引：13

作者：

Lu, Xiaoxiao ^{[1
]}

Mao, Qinzhong ^{[2
]}

Wang, Yinfeng ^{[2
]}

Ji, Tongzong ^{[2
]}

Zeng, Yunhui ^{[1
]}

Xu, Yuankang ^{[1
]}

Xia, Yang ^{[3
]}

Shan, RuiHao ^{[1
]}

Xu, Panpan ^{[1
]}

Cai, Yurong ^{[1
]}

Yao, Juming ^{[1
]}

机构：

[1] Zhejiang Sci Tech Univ, Sch Mat Sci & Engn, Hangzhou 310018, Peoples R China

[2] Zhejiang Hitrans Lithium Technol Co Ltd, Shaoxing 312300, Peoples R China

[3] Zhejiang Univ Technol, Coll Mat Sci & Engn, Hangzhou 310014, Peoples R China

来源：

SURFACES AND INTERFACES | 2023年 / 36卷

基金：

中国国家自然科学基金;

关键词：

Li2ZrO3; NCM811; Surface modification; Lithium-ion battery; OXIDE CATHODE; TRANSITION; LI6ZR2O7;

D O I：

10.1016/j.surfin.2022.102480

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Lithium zirconate (LZO) coatings were routinely applied to NCM cathode materials in industry to improve cyclability and stability, but their working principles remain some elusive. Li/Zr molar ratios for coating preparation in sol-gel route always shows random variations in literature, due to vaporization of lithium source, solid-state diffusion of Zr4+ and formation of residue lithium. In this work, LZO coatings were prepared via a sol-gel route, and chemical compositions and amounts of Zr4+ doping were studied with varying Li/Zr molar ratios. It was found that, the surface composition of LZO was dominated by Li2ZrO3 at a low Li/Zr molar ratio of 2.1, and then Li6Zr2O7 and residue lithium increased with a rising Li/Zr molar ratio. As for the ion doping, Zr4+ preferred to enter crystal lattices of NCM811 at a low Li/Zr molar ratio. The best electrochemical performance was ach-ieved for the LZO modified NCM811 with a Li/Zr ratio of 2.4 (NCM811-LZO2.4), and the reasons could be attribute to modification processes introduced moderate Zr4+ doping and the multiphase LZO (Li2ZrO3 and Li6Zr2O7) coating onto the NCM811, which reduced the surface residue lithium and enhanced transport rate of charge carriers. As a result, the NCM811-LZO2.4 delivers a high coulombic efficiency of 91.4% in the initial cycle, outstanding capacity retention after 500 cycles (193 mAh g-1 at 0.2 C), and a good rate capacity of 155.9 mAh g-1 at 10 C. This work provides a method of tailoring chemical compositions of LZO protective coatings to improve the electrochemical performance of NCM811 materials.

引用

页数：11