Cellulose-based materials have attracted growing interest in the development of advanced energy storage systems owing to their intrinsic sustainability, tunable physicochemical properties, and structural versatility. This review systematically summarizes the key features of cellulose from the perspectives of synthesis, physicochemical characteristics, and structural design, highlighting its unique functionality and adaptability. Furthermore, the roles of cellulose in four critical battery components, i.e., electrode, solid electrolyte interphase, separator, and electrolyte, are comprehensively discussed, emphasizing the properties aligning with the specific requirements of each component. Finally, potential research directions are proposed to guide future development. This review provides a comprehensive framework for understanding the transformative potential of cellulose in sustainable electrochemical energy storage systems as well as a guideline for future studies.