A review on redox hydrogel electrolyte for energy storage devices

Abstract

Redox hydrogel electrolytes have emerged as promising materials for next-generation energy storage systems due to their superior ionic conductivity, mechanical flexibility, and compatibility with a broad range of redox-active species. By combining the structural integrity of solid electrolytes with the efficient ion transport of liquid systems, these hydrogels offer a compelling route to improve the performance and safety of batteries and supercapacitors. This review critically explores the fundamentals of electrochemical energy storage, emphasizing the operating mechanisms of batteries and supercapacitors and the pivotal role of electrolytes in determining device efficiency and longevity. Special focus is given to hydrogel electrolytes, especially redox hydrogel, highlighting their potential to enhance electrochemical performance, extend device lifespan, and reduce environmental and production costs. Recent advancements involve the tailored synthesis of hydrogel matrices and the incorporation of redox-active species to fine-tune ionic mobility and stability. Despite progress, challenges persist in optimizing formulations, understanding ion transport, and scaling up the fabrication. Emerging techniques such as 3D printing and freeze-drying show promise in improving electrolyte architecture and electrode compatibility. Continued innovations in materials design and characterization will be the key to unlocking the full potential of redox hydrogel electrolytes in sustainable, high-performance energy storage technologies.