Depth-of-Discharge Dependent Capacity Decay Induced by the Accumulation of Oxidized Lattice Oxygen in Li-Rich Layered Oxide Cathode

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Zhang, Kang ; Chen, Yilong ; Zhu, Yuanlong ; Zheng, Qizheng ; Tang, Yonglin ; Yu, Dongyan ; Liu, Qirui ; Luo, Haiyan ; Yin, Jianhua ; Zeng, Linhui ; Jiao, Wen ; Liu, Na ; Wang, Qingsong ; Zheng, Lirong ; Zhang, Jing ; Wang, Yongchen ; Zhang, Baodan ; Yan, Yawen ; Huang, Huan ; Shen, Chong-Heng ; Qiao, Yu ; Sun, Shi-Gang:
Depth-of-Discharge Dependent Capacity Decay Induced by the Accumulation of Oxidized Lattice Oxygen in Li-Rich Layered Oxide Cathode.
In: Angewandte Chemie International Edition. (2024) . - e202419909.
ISSN 1521-3773
DOI: https://doi.org/10.1002/anie.202419909

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Abstract

More and more basic practical application scenarios have been gradually ignored/disregarded, in fundamental research on rechargeable batteries, e.g. assessing cycle life under various depths-of-discharge (DODs). Herein, although benefit from the additional energy density introduced by anionic redox, we critically revealed that lithium-rich layered oxide (LRLO) cathodes present anomalously poor capacity retention at low-DOD cycling, which is essentially different from typical layered cathodes (e.g. NCM), and pose a formidable impediment to the practical application of LRLO. We systemically demonstrated that DOD-dependent capacity decay is induced by the anionic redox and accumulation of oxidized lattice oxygen (On−). Upon low-DOD cycling, the accumulation of On− and the persistent presence of vacancies in the transition metal (TM) layer intensified the in-plane migration of TM, exacerbating the expansion of vacancy clusters, which further facilitated detrimental out-of-plane TM migration. As a result, the aggravated structural degradation of LRLO at low-DOD impeded reversible Li+ intercalation, resulting in rapid capacity decay. Furthermore, prolonged accumulation of On− persistently corroded the electrode-electrolyte interface, especially negative for pouch-type full-cells with the shuttle effect. Once the “double-edged sword” effect of anionic redox being elucidated under practical condition, corresponding modification strategies/routes would become distinct for accelerating the practical application of LRLO.