ALL-TEMPERATURE FLEXIBLE SUPERCAPACITORS INCLUDING HYDROGEL ELECTROLYTE

摘要

All-temperature flexible supercapacitors are prepared using a hydrogel electrolyte including a poly(vinyl alcohol) (PVA) substrate a montmorillonite (MMT) dopant, along with a 2M sulfuric acid and dimethyl sulfoxide/water aqueous electrolyte dispersed therein. Incorporation of MMT material enhances the thermal stability of PVA polymers, whereas the DMSO/H2O binary system endows the hydrogel with an ultralow freezing point below −50° C. The hydrogel electrolyte displays good mechanical properties and shows superior electrochemical properties in a wide temperature range. The ionic conductivities are 0.17×10−4 and 0.76×10−4 S cm−1 under operation temperatures of −50 and 90° C., respectively. The supercapacitor exhibits a high specific capacity of 161 F g−1 with a high rate capability and life over 10,000 cycles. The flexible supercapacitors deliver a stable energy supply under various flexible conditions, including bending, twisting, and stretching states, and its capacity does not degrade obviously even after 1,000 bending cycles.