Advances in chitosan materials for supercapacitor applications: A review

Biomass-derived materials have become promising candidates for supercapacitor electrode and electrolyte fabrication, attributed to their inherent advantages, namely renewability, low environmental footprint, and scalable production from abundant natural resources. Notably, Chitosan emerges as a preeminent biopolymer, attributed to its broad commercial accessibility, complete biodegradability, and versatile molecular functionality conferred by pendant amino (-NH₂) and hydroxyl (-OH) groups that support straightforward chemical modification, metal coordination, and hierarchical structure engineering. This review summarizes recent progress on Chitosan-based supercapacitor materials, beginning with device fundamentals and Chitosan physicochemistry. It subsequently conduct a critical examination of three major material classes: I Chitosan-derived porous carbons for electric double-layer electrodes; II Chitosan-templated or Chitosan-composited materials for pseudocapacitive or hybrid electrodes; and III Chitosan-based gel polymer electrolytes. Finally, prevailing bottlenecks in machine learning, multiscale simulation and printable micro-supercapacitors are highlighted, and prospective routes are proposed to develop high-performance, eco-sustainable and industrially viable Chitosan-based energy storage devices.