Preparation of Hydrogel Polymer Electrolyte Membrane for Flexible Supercapacitors

Hydrogel polymer electrolyte membrane for flexible supercapacitors were prepared using polyvinyl alcohol (PVA) and glutaraldehyde (GA)，in which poly (N-vinyl-2-pyrrolidone) (PVP) was added to enhance the swelling ratio of prepared electrolyte membranes in 1 mol/L H2SO4．The structure，morpho-logy，swelling ratio，mechanical property and ionic conductivity of the electrolyte membranes were characterized．The flexible supercapacitors were assembled using prepared electrolyte membranes and graphene paper electrodes. Results show that the tensile strength decrease while the density and size of pores，the swelling ratio and ionic conductivity of the hydrogel electrolyte membranes increase with the increasing of PVP content．When the mass fraction of PVP is 20% in electrolyte membrane, the specific capacitance of flexible supercapacitors is 111 F/g, which shows low dependence of electrochemical performances on temperature and good stability.