Cellulose functional materials for moisture-electric generators: Advantages, strategies, and perspectives

Cellulose-based materials have emerged as promising candidates for moisture-electric generators (MEGs) due to their renewable nature, biodegradability, and versatile structural adaptability. This review comprehensively summarizes recent advancements in functional cellulose materials for MEGs, focusing on their molecular characteristics, modification strategies, and performance optimization. Cellulose, with its abundant hydroxyl groups and hierarchical structure, facilitates ion gradient diffusion and streaming potential mechanisms for moisture-electric conversion. The critical strategies such as chemical functionalization (e.g., carboxylation, sulfonation), physical modulation (e.g., laser-induced graphitization, blending), and pore structure engineering are systematically discussed to enhance surface charge density, ion transport efficiency, and environmental adaptability. Notably, optimized cellulose-based MEGs achieve voltages exceeding 1 V and power density up to 10⁶ nW cm^-², enabling applications in direct-current sources, self-powered sensors, and smart IoT systems. Challenges such as low-humidity performance, environmental adaptability, and sustainability are prospected, with future perspectives highlighting the need for mechanistic studies, multifunctional integration, and sustainable energy ecosystems. This work underscores cellulose’s potential to drive green energy technologies, offering insights for advancing next-generation, eco-friendly MEGs.