材料科学
电化学
阴极
镍
离子
扩散
兴奋剂
氧气
石墨
化学工程
锂(药物)
电极
复合材料
化学
物理化学
冶金
热力学
有机化学
光电子学
医学
物理
工程类
内分泌学
作者
Yu Zhou,Hanwei Zhang,Yinglei Wang,Tao Wan,Peiyuan Guan,Xiao‐Dong Zhou,Xuri Wang,Yi‐Chang Chen,Hanyu Shi,Aichun Dou,Mingru Su,Ruiqiang Guo,Yunjian Liu,Liming Dai,Dewei Chu
出处
期刊:ACS Nano
[American Chemical Society]
日期:2023-10-04
卷期号:17 (20): 20621-20633
被引量:26
标识
DOI:10.1021/acsnano.3c07655
摘要
Nickel-rich LiNi0.8Co0.15Al0.015O2 (NCA) with excellent energy density is considered one of the most promising cathodes for lithium-ion batteries. Nevertheless, the stress concentration caused by Li+/Ni2+ mixing and oxygen vacancies leads to the structural collapse and obvious capacity degradation of NCA. Herein, a facile codoping of anion (F-)-cation (Mg2+) strategy is proposed to address these problems. Benefiting from the synergistic effect of F- and Mg2+, the codoped material exhibits alleviated Li+/Ni2+ mixing and demonstrates enhanced electrochemical performance at high voltage (≥4.5 V), outperformed the pristine and F-/Mg2+ single-doped counterparts. Combined experimental and theoretical studies reveal that Mg2+ and F- codoping decreases the Li+ diffusion energy barrier and enhances the Li+ transport kinetics. In particular, the codoping synergistically suppresses the Li+/Ni2+ mixing and lattice oxygen escape, and alleviates the stress-strain accumulation, thereby inhibiting crack propagation and improving the electrochemical performance of the NCA. As a consequence, the designed Li0.99Mg0.01Ni0.8Co0.15Al0.05O0.98F0.02 (Mg1+F2) demonstrates a much higher capacity retention of 82.65% than NCA (55.69%) even after 200 cycles at 2.8-4.5 V under 1 C. Furthermore, the capacity retention rate of the Mg1+F2||graphite pouch cell after 500 cycles is 89.6% compared to that of the NCA (only 79.4%).
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