Diglyme-based gel polymer electrolytes for K-ion capacitors

In this work, we report a new diglyme-based gel-polymer electrolyte (DOKBn-GPE) suitable for the realization of a potassium-ion capacitor (KIC). We show that this novel gel polymer electrolyte displays good mechanical stability, high ionic conductivity (2.84 mS cm−1 at 20 ◦C), and broad electrochemical stability (> 5.0 V). Its use in KIC makes possible the realization of devices displaying high energy density and high stability during prolonged charge–discharge as well as during float tests. These results are indicating that the development of diglyme-based GPEs is a promising strategy for the application of high-performance K-based energy storage devices.