电解质
电化学
锂(药物)
化学
阴极
溶解
石墨
离子
水解
无机化学
化学工程
电极
物理化学
有机化学
内分泌学
工程类
医学
作者
Jianzhong Yang,Marco‐Tulio F. Rodrigues,Yu Zhou,Seoung‐Bum Son,Kewei Liu,Nancy Dietz-Rago,Lei Cheng,Zhengcheng Zhang,Daniel P. Abraham,Chen Liao
出处
期刊:Journal of The Electrochemical Society
[The Electrochemical Society]
日期:2022-04-01
卷期号:169 (4): 040507-040507
被引量:2
标识
DOI:10.1149/1945-7111/ac613f
摘要
We report 1-(dimethylamino) pyrrole (PyDMA) as an electrolyte additive for high voltage lithium-ion batteries based on LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622)//Graphite with an upper cutoff voltage of 4.4 V. Density Functional Theory (DFT) modeling indicates that the unique structure of PyDMA could be effective in preventing the hydrolysis of LiPF 6 in a carbonate electrolyte, mitigating issues related to HF formation. The calculations also indicated that the additive would oxidize at lower potentials than typical electrolyte solvents, which could lead to protective films at the cathode surface. These expectations were tested using Nuclear Magnetic Resonance (NMR) and extensive electrochemical characterization. NMR studies confirmed the superb dehydrating capability of PyDMA, which successfully prevents HF formation even at high water content. Addition of 0.5 wt% PyDMA resulted in improved capacity retention in full-cells, and also in lower levels of transition metal dissolution from the cathode. Incremental capacity (dQ/dV) analysis indicates that benefits of PyDMA at low concentration (0.5–1 wt%) are associated with decreased rates of Li + -trapping reactions, and that higher concentrations of the additive can lead to isolation of cathode domains. Our study indicates that PyDMA could be a promising electrolyte additive for high voltage lithium-ion batteries at a low concentration.
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