Hydrogels for Flexible/Wearable Supercapacitors

Abstract

Due to security and portability considerations, all-solid-state supercapacitors have been widely studied as the preferred power supply option for wearable devices. Developing flexible electrodes with high specific energy and long cycle life, as well as solid electrolytes with wide operating temperature range and strong mechanical elasticity, are the main challenges for all-solid-state supercapacitors. Hydrogel has special swelling characteristics and water retention function due to its hydrophilic three-dimensional network structure and excellent ionic conductivity and mechanical properties. It is suitable for high-performance flexible wearable supercapacitors as a flexible electrode or solid electrolyte to complete the fast charge and discharge function under the premise of ensuring safety and stability. Therefore, it has attracted the attention of electrochemical materials researchers. In this chapter, the research progress of hydrogels in flexible wearable supercapacitors is introduced, and the chemical composition, assembly structure, performance advantages, and challenges of hydrogels as flexible electrodes or solid electrolytes are discussed in detail, aiming to provide reference and basic data for beginners engaged in hydrogel electrochemical research.