C.L. Cao, H.B. Huang *, Y.D. Li, D.X. Liang, H.P. Li, S.X. Liu * and Z.-S. Wu*

Advanced Powder Materials, 2025, accepted.

The growing demand for sustainable energy storage technologies has driven interest in cellulose-based materials (CBMs) for flexible supercapacitors (FSCs). However, FSCs face challenges such as limited energy density, environmental adaptability, and safety concerns, hindering their full development. To date, no comprehensive review specifically highlights the role of chemistry and structure-property relationships of CBMs in FSCs. This review fills this gap by examining the chemical properties and versatility of cellulose and its derivatives, while providing an overview of the chemistry and design principles of CBMs toward eco-friendly FSCs. We summarize their physicochemical characteristics, assembly methods, and functional modifications, including oxidation, esterification, etherification, grafting polymerization, and crosslinking reactions. Afterwards, we explore the chemistry and structure-function correlations of various forms of cellulose used in FSC components, such as electrodes, solid electrolytes, separators, binders, current collectors, and substrates/encapsulation materials. Finally, we discuss the key challenges and future opportunities for large-scale FSC applications and propose design principles to guide the future evolution of cellulose-based FSCs. By providing insights into the chemistry and engineering strategies of CBMs, this review aims to inspire future research and advance the development of sustainable and high-performance FSCs.