Interchain Spacing Expansion Effect Mediated by Green Solvent System: A Conductive Hydrogel With Multifunctional Energy Storage and Sensing Integration for Flexible Electronics

Abstract

Flexible conductive hydrogels are often hindered by non‐green fabrication, performance trade‐offs, and additive‐dependent functionalization. Herein, we establish a triple strategy of “green preparation–structural synergy–multifunctional integration”. With wood vinegar, deep eutectic solvent, polyvinyl alcohol, chitosan, and tetraethoxysilane as raw materials, the target hydrogel is fabricated via a one‐pot route without toxic auxiliary reagents. The interpenetrating network constructed by rigid inorganic sites and flexible polymer chains endows the material with excellent low‐temperature tolerance down to −20°C, high ionic conductivity of 38.1 mS cm−1, and robust mechanical properties. When used as a gel electrolyte in symmetric supercapacitors, the device achieves an energy density of 7.49 Wh kg−1 and maintains stable cycling over 10 000 times. As a flexible strain sensor, it could capture subtle physical movements for precise Morse code recognition assisted by deep learning. A self‐powered sensing system is fabricated by vertically stacking the supercapacitor and hydrogel sensor, which outputs distinct current signals in response to various deformations. Preliminary explorations in array sensing, encrypted communication and manipulator control further validate the great potential of this hydrogel for constructing an integrated “material–device–system” platform, providing a feasible strategy for developing eco‐friendly, integrative, and intelligent flexible electronics.