Diffusion-determined assembly of all-climate supercapacitors via bioinspired aligned gels

Abstract

Inspired by the naturally occurring anti-freeze mechanisms of biological organisms, herein we introduce an ionic compound (LiTFSI) into zwitterionic polymer networks to enhance the anti-freezing performance of gels. The ionic diffusion of the high viscosity LiTFSI aqueous solution within the aligned gel endows the reswollen polymer electrolyte with excellent freeze-tolerance and high ionic conductivity. Interestingly, ion can act as binders to promote tight adhesion between the aligned gel electrolyte and a porous electrode. The resulting well-designed supercapacitors are superior to traditional PVA gel based devices with respect to their electrochemical window (2.5 V) and energy density (52.3 W h kg⁻¹). Furthermore, the devices are facilely assembled, possess a broad range of working temperatures (−54 to 100 °C), and exhibit remarkable flexibility under consecutive bending conditions. Ultimately, this study provides new insight and motivation for the development of robust supercapacitors suitable for complex and harsh environments.