Synergistic Design of Biomass Materials for Moisture‐Induced Electricity Generation

ABSTRACT Harvesting the dispersed, low‐grade energy stored in atmospheric moisture has emerged as an attractive route toward distributed and sustainable power generation. Moisture‐induced electricity generation (MEG) converts chemical potential changes associated with water sorption, ion dissociation, selective ion transport, and interfacial charge transfer into electricity without requiring light, wind, or a liquid water supply. Natural biomass is a promising material platform because its polar and ionizable groups and hierarchical pore channels support moisture uptake, carrier generation, and directional ion transport. However, a single biomass material is unlikely to simultaneously provide high ionic conductivity, a persistent gradient, efficient charge collection, and wet‐state stability. This minireview presents a synergistic design framework across molecular, structural, and device levels. Biomass chemistry regulates carrier generation and ion selectivity, hierarchical structures maintain water activity and ion concentration gradients, and device integration coordinates ionic transport, charge collection, and structural stability. We first outline the fundamental mechanism of biomass‐based MEG and then compare cellulose, sodium alginate, lignin, proteins, chitosan, and microbial materials in terms of their properties, functions, limitations, and suitable application scenarios. Performance optimization strategies are further summarized as ionic regulation, gradient construction, and composite integration. Finally, we discuss the main challenges of conversion efficiency, operating lifetime, wet‐state durability, and biomass variability, together with future directions for practical and sustainable moisture energy harvesting.