Comprehensive Insights into Electrolytes and Solid Electrolyte Interfaces in Potassium-Ion Batteries

Potassium-ion batteries (KIBs) are competitive alternatives to lithium-ion batteries (LIBs) due to the abundant K resources and high energy density. As an indispensable part of the battery, the electrolyte affects the battery capacity, rate capability, cycle life, and safety. Nevertheless, the researches on electrolytes and corresponding solid electrolyte interfaces (SEI) in KIB are still in its infancy and require further attention. In this review, recent progresses of various K+ containing electrolytes for KIBs are summarized comprehensively. Additionally, the effects of salts, solvents, additives, and concentrations on the properties of various electrolyte systems are discussed in detail. Thereafter, interface chemistry between electrode and electrolyte, as well as rational modification strategies for high-performance KIB are reviewed. Finally, the major challenges and the future perspectives are estimated for advanced KIB. This review will provide good directions for the development of high-performance KIB.