Synergetic Electrolyte Chemistry Enables Flame-Retardancy, K+-Desolvation, Anti-Corrosion and Wide-Temperature-Tolerance in Potassium-Ion Batteries

-DME interaction through steric hindrance. While FEMC preempts the DME-induced corrosion of the potassium anode by facilitating the formation of a KF-enriched interface. Consequently, ether cointercalation into graphite is successfully suppressed in K||graphite cells, exhibiting 96% capacity retention over 1800 cycles (a running time of 402 days). When the temperature drops from 50 to -20 °C, the K-ion full device retains a capacity as high as 89%. The study introduces a novel electrolyte regulation strategy that harmonizes intrinsic safety, rapid kinetics at subzero temperatures, and enduring cycle stability at the same time, thereby advancing the practical implementation of PIBs for the future.