A low-cost PAN-b-PEG-b-PAN/TEABF4 gel electrolyte for flexible all-solid-state supercapacitors

In this study, we present our findings on a soft gel-polymer electrolyte (GPE) utilizing a triblock copolymer, poly(polyacrylonitrile-block-polyethylene-block-polyacrylonitrile) (PAN-b-PEG-b-PAN), combined with the plasticizer N, N-dimethylformamide (DMF) and the ionic liquid tetrafluoroborate ammonium (TEABF4). We engineered a flexible all-solid-state electric double-layer capacitor (EDLC) cell to exploit this GPE. The conductivity of the gel copolymer electrolyte was optimized by fine-tuning the mass ratio of the components. Thermal stability tests showed stable GPE film dimensions even at 120 °C with a fiber separator. The optimized EDLC cell demonstrated a broad 2.7 V potential window, high specific capacitance (142.15 F g−1), and energy density (518.14 J g−1) at a discharge rate of 0.01 A g−1. Cycling studies revealed a modest 9 % capacitance loss after 3000 charge-discharge cycles, maintaining a stable open-circuit voltage (70 % from 2.7 V to 1.9 V) after 25 h self-discharge process. These results highlight the potential of the GPE in all-solid-state supercapacitor applications. •Soft gel-copolymer triblock copolymer (PAN-b-PEG-b-PAN) loaded with TEABF4 for flexible super capacitators.•As-prepared GPE membrane in fibrous paper keeps their dimension over a wide temperature range.•The optimized GPE membrane exhibits a high ionic conductivity at room temperature.•The optimized EDLC cell delivers a wide potential window of 2.7 V.