Interface problems, modification strategies and prospects of Ni–rich layered oxide cathode materials in all–solid–state lithium batteries with sulfide electrolytes

All–solid–state lithium batteries (ASSLBs) using sulfide solid electrolytes (SSEs) have triggered extensive attentions in both academia and industry due to the feasibility of effectuating high safety and high energy density, compared with liquid–type batteries. Cathode materials with high voltage and prominent specific capacity are urgently needed for realizing lithium batteries with high energy density. Among multitudinous cathode materials studied by researchers, Ni–rich layered oxide cathode materials are considered to be one of the most promising applications in ASSLBs due to high operating voltage, superior reversible capacity and low production cost. However, their physical, chemical, and electrochemical performances in ASSLBs, especially the long–life capacity, are still insufficient to gratify market requirements for electric vehicles, and the targeted review for Ni–rich layered oxide cathodes in ASSLBs is rare. Herein, we comprehensively summarize these issues of the interfacial physical connection, chemical/electrochemical reactions, and space–charge layer (SCL) of Ni–rich layered oxide cathodes in ASSLBs with SSEs. Moreover, the modification strategies of Ni–rich layered oxide cathode materials to address the aforementioned issues are focused on. In the end, the future development direction of ASSLBs using Ni-rich oxide cathodes and SSEs is briefly discussed.