In situ epitaxial growth and electrochemical conversion of LiNi0.5Mn1.5O4 thin layer on Ni-rich cathode materials for high voltage lithium-ion batteries

Cong Li; Chun Liu; Honglei Liu; Chengzhi Hu; Yong Wu; Afei Li; Zhangxian Chen; Zeheng Yang; Weixin Zhang

doi:10.1039/d3nr00780d

In situ epitaxial growth and electrochemical conversion of LiNi_0.5Mn_1.5O₄ thin layer on Ni-rich cathode materials for high voltage lithium-ion batteries

Nanoscale. 2023 May 25;15(20):9187-9195. doi: 10.1039/d3nr00780d.

Authors

Cong Li^{1

2}, Chun Liu¹, Honglei Liu¹, Chengzhi Hu¹, Yong Wu¹, Afei Li¹, Zhangxian Chen^{1

2}, Zeheng Yang¹, Weixin Zhang^{1

2}

Affiliations

¹ School of Chemistry and Chemical Engineering, Hefei University of Technology and Anhui Key Laboratory of Controllable Chemical Reaction & Material Chemical Engineering, Hefei, Anhui, 230009, China. zehengyang@hfut.edu.cn.
² Institute of Energy, Hefei Comprehensive National Science Center, Hefei, Anhui, 230031, China.

PMID: 37144981
DOI: 10.1039/d3nr00780d

Abstract

Ni-rich LiNi_xCo_yMn_1-x-yO₂ (0.5 < x < 1) cathode materials have attracted considerable interest due to their high energy density and low cost. However, they are subject to capacity fading during cycling, such as structural degradation and irreversible oxygen release, especially under high voltage. Herein, we report an in situ epitaxial growth strategy to construct a thin layer of LiNi_0.25Mn_0.75O₂ on the surface of LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811). Both of them share the same crystal structure. Interestingly, the LiNi_0.25Mn_0.75O₂ layer can be electrochemically converted into a stable spinel LiNi_0.5Mn_1.5O₄ (LNM) due to the Jahn-Teller effect under high voltage cycling. The derived LNM protective layer can effectively alleviate the harmful side reactions between the electrode and electrolyte and suppress oxygen release as well. Furthermore, the coating LNM layer can enhance Li⁺ ion diffusion due to its three-dimensional channels for Li⁺ ion transport. When used as half-cells with lithium as the anode, NCM811@LNM-1% realizes a large reversible capacity of 202.4 mA h g^-1 at 0.5 C, with high capacity retention of 86.52% at 0.5 C and 82.78% at 1 C, respectively, after 200 cycles in the voltage range of 2.8-4.5 V. Moreover, the assembled pouch full-cell with NCM811@LNM-1% as cathode and commercial graphite as an anode can deliver 11.63 mA h capacity with a high capacity retention of 80.05% after 139 cycles in the same voltage range. This work demonstrates a facile approach to the fabrication of NCM811@LNM cathode materials for enhancing performance in lithium-ion batteries under high voltage, rendering its promising applications.