In order to enhance the energy density of lithium-ion batteries (LIBs), the development of solid-state electrolytes (SSEs) has become imperative. In particular, inorganic SSEs are gaining attention due to their inherent merits, including nonflammability and a wide operating temperature range. Among these, sulfide- and oxide-based SSEs stand out owing to their high ionic conductivity and excellent chemical stability, respectively. However, despite these advantages, achieving good interfacial compatibility between SSEs and the cathode and anode in full cells to address issues such as interfacial side reactions and high interfacial impedance remains a major challenge in the development of high-performance solid-state electrolytes. This review first examines the structural and chemical similarities and differences between oxide and sulfide SSEs, and it elucidates the mechanisms of interfacial side reactions. It then discusses recent advances in three strategies aimed at addressing these interfacial issues: element doping, artificial SEI layers, and electrode material modifications. Lastly, the review provides a comprehensive overview of interfacial challenges specific to sulfide and oxide SSEs and offers perspectives on the future development of solid-state electrolytes.
Ren et al. (2025) studied this question.