Progress and perspective of the cathode/electrolyte interface construction in all-solid-state lithium batteries

Security risks of flammability and explosion represent major problems with the use of conventional lithium rechargeable batteries using a liquid electrolyte. The application of solid-state electrolytes could effectively help to avoid these safety concerns. However, integrating the solid-state electrolytes into the all-solid-state lithium batteries is still a huge challenge mainly due to the high interfacial resistance present in the entire battery, especially at the interface between the cathode and the solid-state electrolyte pellet and the interfaces inside the cathode. Herein, recent progress made from investigations of cathode/solid-state electrolyte interfacial behaviors including the contact problem, the interlayer diffusion issue, the space-charge layer effect, and electrochemical compatibility is presented according to the classification of oxide-, sulfide-, and polymer-based solid-state electrolytes. We also propose strategies for the construction of ideal next-generation cathode/solid-state electrolyte interfaces with high room-temperature ionic conductivity, stable interfacial contact during long cycling, free formation of the space-charge region, and good compatibility with high-voltage cathodes.