电解质
碳酸乙烯酯
碳酸二乙酯
化学
电极
锂(药物)
碳酸二甲酯
石墨
碳酸盐
分析化学(期刊)
电感耦合等离子体质谱法
质谱法
无机化学
色谱法
催化作用
有机化学
物理化学
内分泌学
医学
作者
Lauren Thompson,W J D Stone,Ahmed Eldesoky,Nathan K. Smith,Christopher R.M. McFarlane,Jong Sung Kim,Michel B. Johnson,R. Petibon,J. R. Dahn
出处
期刊:Journal of The Electrochemical Society
[The Electrochemical Society]
日期:2018-01-01
卷期号:165 (11): A2732-A2740
被引量:71
摘要
A set of LiNi0.5Mn0.3Co0.2O2/graphite lithium-ion cells underwent 750 charge-discharge cycles during about 8 months at 55°C to upper cutoff potentials of 4.0, 4.1, 4.2, 4.3, and 4.4 V. The electrolyte in these cells was extracted using a centrifuge method and studied using gas chromatography/mass spectrometry to determine the changes to the solvents and by inductively coupled plasma-mass spectrometry to determine the changes to the salt content in the electrolyte. The negative electrodes from the cells were harvested and studied by micro-X-ray fluorescence to quantify the amount of transition metals which migrated from the positive electrode to the negative electrode during the testing. Emphasis is given to a detailed description of the quantitative methods used in the hope that others will adopt them in similar studies of different types of aged lithium-ion cells. The cells studied here initially had 1.1 molal LiPF6 ethylene carbonate (EC): ethyl methyl carbonate (EMC) (3:7 by weight) electrolyte. The aged cells showed increasing amounts of dimethyl carbonate and diethyl carbonate created by transesterification as the upper cutoff potential increased. Only extremely small amounts of Mn, less than 0.1% of the total Mn in the positive electrode, were found on the negative electrode after this aggressive testing.
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