Fabrication of novel Hydrogel/Epoxy resin composites with Soft-Hard combined Bi-Continuous aqueous load-bearing electrolytes and application in structural energy storage devices

Abstract

Structural electrolytes with both mechanical and electrochemical properties are of great significance in structural energy storage devices. In this paper, we succeeded to synthesize a novel epoxy resin/hydrogel bicontinuous phase structure electrolyte for the first time by the ingenious design of the hydrophobic curing agent and the substitution of hydrogel for water, and filled the application of bicontinuous electrolyte in aqueous electrochemical energy storage system. The fine structure composition of electrolyte was divided and analyzed in detail by X-ray micro-CT technology. The epoxy resin phase is composed of a reasonable distribution of skeleton structures of various sizes, the largest of which is able to support heavy weights. And a large number of tiny skeletons are distributed to connect the skeletons of different sizes, which improves the three-dimensional interconnection of the epoxy resin phase and makes it excellent mechanical properties (Tensile strength 11.91 Mpa). The large size PVA gel phase constitutes the main pathway for conducting ions. Furthermore, the large-diameter gel phases are coupled in three dimensions with a huge number of micro-diameter gel phases, increasing the number of micro-ion transport channels and decreasing the distance of ion transport with good ionic conductivity (0.15 mS cm−1). Using carbon cloth coated in slurry as the electrode, an integrated structural energy storage bearing device was created in situ using layer brush technology, which exhibited exceptional electrochemical performance during in-situ variable load tests. We have successfully solved the construction of aqueous bicontinuous phase structure electrolyte, which made the application of various water chemistry systems in structural energy storage possible.