Development of Nonaqueous Electrolytes for High-Voltage K-Ion Batteries

K-ion batteries (KIB) are a widely attractive alternative to Li-ion batteries (LIB). While avoiding scarce/toxic elements in their construction, the low standard electrode potential of K⁺/K allows a low cut-off potential of the negative electrode and high operation voltages that are competitive with those observed in LIB. Because of the wide operating potential range, developing improved non-aqueous electrolytes with higher oxidation stability and the ability to passivate low-potential negative electrodes is one of the major challenges of high voltage KIB production. Recent studies on non-aqueous electrolytes design based on potassium salt and solvent properties are discussed along with the emerging challenges and provide our perspective on nonaqueous electrolytes for high-voltage KIB.