期刊
ELECTROCHIMICA ACTA
卷 318, 期 -, 页码 875-882出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.electacta.2019.06.119
关键词
Voltage fade; Li-rich cathode material; Structure change; Cations rearrangement; Lithium-ion batteries
资金
- National Key R&D Program of China [2016YFA0202602]
- National Natural Science Foundation of China [U1663225, 21671155, 21805220]
- Natural Science Foundation of Hubei Province [2018CFB242, 2018CFA054]
- Major Technology Innovation of Hubei Province [2018AAA012]
- Program for Changjiang Scholars Innovative Research Team in University [IRT_15R52]
The voltage fade of Li-rich layered oxide cathode material Li1.2Ni0.13Co0.13Mn0.54O2 (LNCM) heavily hinders its application in Li-ion batteries. Herein, we revisit the origin of the voltage fade of LNCM and propose a solution to suppress this effect. It is demonstrated that the voltage fade of the LNCM cathode comes from the structural change of the crystal from layer structure to spinel structure, involving all the cations rearrangement. Such rearrangement of all the cations in LNCM is due to the high degree of delithiation and oxygen release at high cutoff voltage of 4.8 V. It is also evidenced that nickel and cobalt change from low valence to high valence at the discharged state, which not only inhibits the transport of lithium ions, but also leads to the loss of high voltage platforms. In particular, the cation rearrangement of Li/Mn causes valence change from Mn4+ to Mn3+, resulting in the decrease of discharge voltage platform at the cutoff voltage of 4.8 V much higher than at 4.6 V. The lower charge cutoff voltage can be a solution to suppress the voltage fade of LNCM cathode materials and have a good stability of LNCM cathode materials without compromising the battery performance. (C) 2019 Elsevier Ltd. All rights reserved.
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