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
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.
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页数:11
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