尖晶石锰酸锂人工CEI膜修饰及其高温性能改性研究
Artificial CEI modification for spinel lithium manganate and its high temperature performance
蒋庆来 1阳文辉 1张霞1
作者信息
- 1. 长沙职业技术学院汽车工程学院,湖南长沙 410217
- 折叠
摘要
锂离子电池尖晶石型锰酸锂正极材料具有较低的成本与优异的安全性能,但其电压平台较高,所产生较厚的正极界面相(CEI)可导致电池极化增加.此外,由于锰元素的溶解而导致的电池循环性能衰减亦严重制约着其在高温条件下的应用.实验从锰酸锂正极材料的人工CEI膜修饰入手,通过电解质/电极界面电化学稳定性的增强,解决了界面副反应与锰溶解的问题.采用硅酸锂作为人工CEI膜材料包覆层包覆锰酸锂,将60 ℃下全电池的首圈库伦效率提高了 11.2％,并将60 ℃下锰元素的溶解率降低了10.9％.所组装的锰酸锂/石墨全电池1 000圈容量保持率从57.3％提升至82.2％.此外,通过对石墨负极表面残锰的检测发现,全电池电化学性能的提高一方面源于正极锰溶解的抑制,另一方面源于负极表面残锰的减少.通过硅酸锂作为人工CEI膜修饰策略可为尖晶石型锰酸锂正极材料高温性能的提升提供有效途径.
Abstract
Spinel lithium manganate cathode material for lithium-ion battery possess the advantages of cost-effec-tiveness and high safety. However,the high voltage platform of lithium manganate is higher,thus resulting in a thick cathode-electrolyte interphase (CEI) and increasing the polarization. In addition,the degradation of battery cycle performance due to the dissolution of manganese also seriously restricts its application at high temperature.In this study,the problems of side reactions and manganese dissolution were solved by improving the electro-chemical stability of electrolyte/electrode interface by modifying the lithium manganate cathode material with ar-tificial CEI. By applying lithium silicate as the artificial CEI coating layer,the first cycle coulomb efficiency of the full cell at 60 ℃ is increased by 11.2％,and the dissolution rate of manganese at 60 ℃ is decreased by 10.9％. The capacity retention of the lithium manganate/graphite full battery after 1 000 cycles is increased from 62.2％ to 83.5％. In addition,through the detection of manganese residue on the surface of the graphite anode,it is found that the electrochemical performance improvement is attributed to the inhibition of the dissolution of manganese in the positive electrode and the reduction of manganese residue on the negative electrode. The strate-gy of applying lithium silicate as an artificial CEI modification provides an effective way to improve the high temperature performance of spinel lithium manganate cathode materials.
关键词
锰酸锂/CEI膜/硅酸锂/高温性能/锂电子电池Key words
lithium manganate/CEI film/lithium silicate/high temperature performance/LIB引用本文复制引用
基金项目
湖南省科技厅自然科学基金资助项目(2023JJ60268)
出版年
2024
NETL
NSTL
万方数据