Disulfonated polyarylene ether sulfone membrane for graphitic carbon nitride/zinc oxide based photo-supercapacitors

•The novel photo-supercapacitor design with Li+- biphenol-based disulfonated poly (arylene ether sulfone) random copolymer.•Defect-mediated light-induced charge trapping observed via EPR for g-C3N4/ZnO photo-electrode.•Excellent cycling stability over 30,000 charge/discharge cycles with capacitance retention and Coulombic efficiency of 96% and 100%, respectively.•2.8 times higher specific capacitance at UV compared to the dark condition.•5.5 times higher energy density at 100% humidity and 85 °C compared to ambient conditions.