The synergistic effect of nitrile and ether functionalities for gel electrolytes used in supercapacitors

This study examines the linear triblock copolymer design of poly(acrylonitrile)-b-poly(ethylene glycol)-b-poly(acrylonitrile) (PAN-b-PEG-b-PAN) for a gel polymer electrolyte (GPE) swollen with dimethylformamide dissolving LiClO₄. The study demonstrates the synergistic effect of the nitrile and ether functionalities in facilitating ion transport in the carbon films of electric double-layer capacitors (EDLCs). A GPE with a tuned AN/EG ratio exhibits ionic conductivity at approximately 10 ^-2 S cm^-1. The linear configuration incorporates the GPE border into the carbon electrodes. The PAN chain promotes ion solvation and transport into the carbon interior, and the PEG chain coordinates the solvent molecules to form ion motion channels. The synergistic effect of the PAN and PEG blocks enables a GPE EDLC delivering more energy and power than EDLCs with a liquid-phase electrolyte. The GPE EDLC delivers 20 Wh kg^-1 (approximately 10 Wh L^-1) at a high power of 10 kW kg^-1 (approximately 5 kW L^-1) when using a high-porosity carbon electrode derived from mesophase pitch activation.