Self-healing hydrogels in flexible energy storage devices: mechanisms, applications, and prospects

Abstract

Self-healing hydrogels, as an advanced material with dynamically reversible network structures, have recently demonstrated significant potential in flexible energy storage devices. This review systematically summarizes the latest research progress of self-healing hydrogels in flexible energy storage systems such as supercapacitors, lithium/sodium-ion batteries, and zinc-ion batteries. The multiple self-healing mechanisms based on dynamic covalent bonds (including disulfide bonds and acylhydrazone bonds) and non-covalent interactions (such as hydrogen bonds and metal coordination) are highlighted in advance. After that, the strategy of design and structural regulation, which can achieve a synergistic balance between mechanical strength, conductivity, stretchability, and self-healing performance, is discussed. Notably, their unique ability to maintain stable electrochemical performance under extreme conditions (such as low temperature, high humidity, and mechanical damage) is exhibited. At last, the current challenges of self-healing hydrogel electrolytes, including theoretical modeling, multi-functional integration, device-level self-healing, and large-scale fabrication, are proposed, which aim to sustainably drive rapid progress going forward in this field.