(Invited) Gel Polymer Electrolytes with Postinjection Gelation and High-Voltage Features for Double Layer Capacitors

Abstract

For ensuring safety and for the development of flexible devices, gel polymer electrolytes (GPEs) are ideal substitutes for the liquid electrolytes (LEs) currently used in batteries and capacitors. However, the use of GPEs is limited by the liquid injection assembly line currently used in battery and capacitor manufacturing. This study reports electric double layer capacitors (EDLCs) made from a postinjection gelated GPE, which is synthesized by mixing poly(acrylonitrile-co-methyl acrylate) and LE. This research indicates that the functionalities on the polymer chains of the GPE facilitate the dissociation of ion pairs and suppress the formation of ion-solvent complexes. Therefore, the ionic conductivity of the GPE is an order of magnitude higher than that of the LE. Under polarization for dielectric analysis, the GPE exhibits high storage permittivity and low loss permittivity because of its swift ion motion and polymeric dipole orientation. The cycling stability and energy and power densities of the resulting GPE-EDLC are higher than those of the LE-EDLC. As incorporated with graphene-based materials, this GPE exhibits low flammability and high voltage stability. The postinjection gelation feature and outstanding electrochemical properties of this GPE enable its industrial application.