Water-in-Salt Electrolyte for Potassium-Ion Batteries

Concentrated potassium acetate as a water-in-salt electrolyte provides a wide potential window from −1.7 to 1.5 V vs Ag/AgClKCl sat.. It facilitates the reversible operation of KTi2(PO4)3, an anode of potassium-ion batteries, that otherwise only functions in nonaqueous electrolytes.