Poly(vinylidene fluoride-co-hexafluoropropylene) and 4,5-Diamino-6-hydroxy-mercaptopyrimidine Based Gel Polymer Electrolytes for High-Performance Supercapacitor Devices

Gel polymer electrolytes (GPEs) were prepared in poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF- co -HFP) as host polymer by incorporating tetraethylammonium tetrafluoroborate (TEA-BF 4 ) in adiponitrile (ADN) followed by adding 4,5-diamino-6-hydroxy-mercaptopyrimidine (DAHMP) as an additive. The performance of GPEs was optimized by varying the TEA-BF 4 concentration, as well as using different additives. The highly flexible GPE has shown a high ionic conductivity of 8.3 mS cm –1 at room temperature. A well-studied electrode material, nitrogen-enriched nanoporous polytriazine (NENP), was used as an active electrode material for fabricating symmetric supercapacitor devices (SCDs), which have shown a specific capacitance ( C sp ) of 104 F g –1 and specific energy ( E sp ) and power densities of 106.5 Wh kg –1 and 22.8 kW kg –1 . Even after 10,000 charge–discharge cycles, the SCD retained 87% of initial capacitance with high Coulombic efficiency of 99–100% at 2 A g –1 . The high performance of SCD could be attributed to the presence of different functional groups in GPE.