A gradient oxy-thiophosphate-coated Ni-rich layered oxide cathode for stable all-solid-state Li-ion batteries

作者：Jianwen Liang, Yuanmin Zhu, Xiaona Li, Jing Luo, Sixu Deng, Yang Zhao, Yipeng Sun, Duojie Wu, Yongfeng Hu, Weihan Li, T. Sham, Ruying Li, M. Gu, X. Sun · 发表于：Nature Communications · 年份：2023 · DOI：10.1038/s41467-022-35667-7 · 被引用次数：164 · 研究领域：Medicine

High-energy Ni-rich layered oxide cathode materials such as LiNi_0.8Mn_0.1Co_0.1O_2 (NMC811) suffer from detrimental side reactions and interfacial structural instability when coupled with sulfide solid-state electrolytes in all-solid-state lithium-based batteries. To circumvent this issue, here we propose a gradient coating of the NMC811 particles with lithium oxy-thiophosphate (Li_3P_1+xO_4S_4x). Via atomic layer deposition of Li_3PO_4 and subsequent in situ formation of a gradient Li_3P_1+xO_4S_4x coating, a precise and conformal covering for NMC811 particles is obtained. The tailored surface structure and chemistry of NMC811 hinder the structural degradation associated with the layered-to-spinel transformation in the grain boundaries and effectively stabilize the cathode|solid electrolyte interface during cycling. Indeed, when tested in combination with an indium metal negative electrode and a Li_10GeP_2S_12 solid electrolyte, the gradient oxy-thiophosphate-coated NCM811-based positive electrode enables the delivery of a specific discharge capacity of 128 mAh/g after almost 250 cycles at 0.178 mA/cm^2 and 25 °C. Layered oxide cathode active materials suffer from interfacial structural instability when coupled with sulfide solid-state electrolytes. Here, the authors propose a gradient coating with a lithium oxythiophosphate layer that can stabilize the cathode|solid-state electrolyte interface.