Cellulose-based materials for advanced energy storage: Sustainable extraction, hierarchical design, and battery applications

The rapid advancement of electrochemical energy storage technologies has created an urgent demand for sustainable, high-performance, and safe battery materials. Among renewable biomass resources, cellulose has emerged as a promising candidate because of its abundance, renewability, mechanical robustness, tunable surface chemistry, and excellent affinity for electrolytes. This review first presents a comprehensive overview of cellulose sources, including plant-derived, bacterial, and algal cellulose, and discusses the major extraction approaches used to obtain high-purity cellulose, including chemical, mechanical, and emerging green extraction technologies based on ionic liquids, deep eutectic solvents, and supercritical fluids. The hierarchical structure of cellulose is then examined from molecular chains and elementary fibrils to microfibrils, macrofibrils, and fiber-level architectures, highlighting how crystalline and amorphous domains are organized within nanofibrillar networks. Particular emphasis is placed on the relationship between these multiscale structural features and the resulting mechanical strength, ionic transport behavior, thermal stability, electrolyte affinity, and interfacial characteristics. Building on these structure–property relationships, the review systematically analyzes the application of cellulose-based materials in advanced battery systems, including lithium-ion, sodium-ion, potassium-ion, zinc-ion, lithium–sulfur, and solid-state batteries. The multifunctional roles of cellulose as binders, separators, and gel or solid polymer electrolyte frameworks are discussed, with attention to dendrite suppression, electrolyte uptake, interface stabilization, and cycling performance enhancement. Finally, the remaining challenges related to scalability, moisture sensitivity, ion-transport optimization, and standardization are critically evaluated, and future directions for integrating cellulose-based materials into next-generation sustainable energy-storage technologies are outlined.