Understanding and Design of Cathode–Electrolyte Interphase in High‐Voltage Lithium–Metal Batteries

The development of lithium–metal batteries (LMBs) has emerged as a mainstream approach for achieving high‐energy‐density energy storage devices. The stability of electrochemical interfaces plays an essential role in realizing stable and long‐life LMBs. Despite extensive and comprehensive research on the lithium anode interface, there is limited focus on the cathode interface, particularly regarding high‐voltage transition metal oxide cathode materials. In this review, the challenges associated with developing stable high‐voltage cathode materials are first discussed. Characterization techniques for understanding the composition and structure of the cathode–electrolyte interphase (CEI) are then introduced. Subsequently, recent developments in electrolyte design and interface modification for constructing a stable CEI are summarized. Finally, perspectives on future research trends for understanding and developing the high‐voltage CEI are discussed. This review can offer valuable guidance for understanding and designing the high‐voltage CEI, pushing forward the development of high‐energy‐density LMBs. This review summarizes the challenges faced with the cathode–electrolyte interphase (CEI) in high‐voltage lithium–metal batteries (LMBs), advanced characterization techniques for understanding the CEI chemistry and structure, as well as the recent developments in constructing stable CEI. Moreover, a perspective for the future research trends of the CEI is offered, serving as a guide for advancing the development of high‐energy‐density LMBs.