Use of a superbase/DMSO/CO2 solvent in order to incorporate cellulose into organic ionogel electrolyte for flexible supercapacitors

The facile preparation of sustainable polymer gel electrolyte by using renewable natural polymers has attracted much attention, and the development of new polymer gel electrolyte materials largely depends on the facile design and preparation of a polymer network capable of effectively loading external high-performance electrolyte. In this study, taking the advantages of a newly developed solvent system superbase/DMSO/CO2 for cellulose, a new and facile "all-in-one" strategy to engineer cellulose into flexible cellulosic poly (protic ionic liquids)/PVA-based composite organic ionogel electrolyte (CPOIE) has been developed through in situ derivatization, chemical cross-linking and compositing strategy using succinic anhydrides, epichlorohydrin, and polyvinyl alcohol, respectively. The findings show that CPOIEs exhibit both excellent mechanical properties and superior electrochemical properties (high ionic conductivity up to 4.2 mS/cm at room temperature with a wide electrochemical window of 2.0 V for C1P1OIE sample). A supercapacitor assembled by using the as-prepared C1P1OIE sample delivers a good specific capacitance of 122 F/g at 0.5 A/g, a high energy density up to 17.38 Wh/Kg at room temperature and an excellent cyclic stability up to 8000 cycles.