Modulating the internal porosity of organogel electrolyte via pore-forming agent for low temperature resistant and flexible quasi-solid supercapacitors

Abstract

The widely applicable gel polymer electrolytes (GPEs) hold significant promise for the commercialization of low-temperature flexible quasi-solid-state supercapacitors (FQSCs). However, their flexibility and electrochemical performance are compromised under extreme cold conditions, severely limiting their practical applications. Inspired by the novel effects of “pore-form agents (PFA)”in hydrogel-controlled drug release & delivery, polyvinyl alcohol (PVA) hydrogel electrolytes with optimized internal porosity (polymeric structure) were prepared by introducing PFA as pore-regulator and in-situ leaching process, hereby enhancing the hydrogel's electrical conductivity and low-temperature performance. Furthermore, in order to further enhance its low-temperature tolerance, the composition of the electrolyte was adjusted via binary solvent replacement method. FQSCs composed of PVA-PFA30-EG exhibited significantly improved high specific capacitances of 131.72 F g−1 at 25 °C and 72.90 F g−1 at −40 °C when tested at 1 A g−1, with only a 6.36 % capacitance decay after 10,000 cycles at −40 °C. This performance surpasses that of most previously reported low-temperature FQSCs. The novel approach proposed in this paper provides a new avenue for flexible energy storage devices in extremely cold conditions.