Inorganic salt grafted ionic liquid gel electrolytes for efficient solid state supercapacitors: Electrochemical and dielectric studies

Developing a solid state supercapacitor with high specific capacitance, increased energy density, wide voltage window and enhanced power density has motivated the research community for quite sometimes. Choosing an apt solid-state gel electrolyte with superior ion migration rate, realistic mechanical strength, robustness, improved thermal stability is the challenge to achieve the above goal. Here, we report an inorganic salt grafted ionic liquid electrolyte bonded in polymer matrix gel electrolyte, which brings high conductivity, wide potential window and fast charge transfer between electrolyte and electrode, establishing a superior electrochemical performance in our graphene-based solid-state supercapacitor. Thus, we achieved the best value among the previously reported graphene-based solid-state supercapacitors with a specific capacitance of 826 F/g at 10 mV/s with excellent cyclic stability, high energy density of 37.1 KW/Kg, wide voltage window of 3 V and high thermal stability up to 3350C.