Abstract
Nickel-rich layered material has been considered as the most promising one for lithium ion batteries due to its high specific capacity. To further improve the lifetime performance, it is significant to investigate the degradation mechanisms deeply. In this study, the degradation mechanism of NCM811 (LiNi0.83Co0.12Mn0.05O2) being cycled at 45oC was systematically researched. Electrochemical impedance spectrum (EIS) results showed that the SEI resistance (RSEI) and charge transfer resistance (Rct) went up to 83.41% and 211.34% before and after the NCM811 material being cycled at 45oC, respectively. The main factors that influenced the RSEI and Rct were analyzed by means of XPS, TEM, XRD and XANES. The increase of RSEI was mainly ascribed to the conversion of some organic components to inorganic components such as lithium carbonate. Besides, the thickness of SEI film increased due to the side product of lithium fluoride (LiF) accumulated around the active materials. The increase of Rct was ascribed to the destruction of crystal structure, the phase transformations from R-3m to Fd-3m and to Fm-3m, and the micro-cracks appeared inside of the active particles. In addition, the solid mass transfer resistance (Rw) was found to become larger, which was mainly affected by the enhanced Li/Ni mixing and dissolutions of transition metal elements.
Graphical Abstract
Keywords
LiNi0.83Co0.12Mn0.05O2, 45 °C cycle degradation, electrochemical impedance spectrum, solid electrolyte interphase, charge transfer resistance
Publication Date
2020-06-28
Online Available Date
2019-04-09
Revised Date
2019-03-29
Received Date
2019-01-23
Recommended Citation
Hong-yun MA, Xiao-hui YAO, Meng-yao MIAO, Yang YI, Shao-zhong WU, Jiang ZHOU.
Degradation Mechanism of LiNi0.83Co0.12Mn0.05O2 Cycled at 45 oC[J]. Journal of Electrochemistry,
2020
,
26(3): 431-440.
DOI: 10.13208/j.electrochem.190123
Available at:
https://jelectrochem.xmu.edu.cn/journal/vol26/iss3/14
Included in
Engineering Science and Materials Commons, Materials Chemistry Commons, Materials Science and Engineering Commons, Physical Chemistry Commons
