High-Power Hydrogel-Based Moisture-Electric Generators

Moisture-electric generators (MEGs) represent an emerging off-grid energy technology capable of generating electricity from ambient humidity; however, the power density and operational durability of existing MEG devices remain suboptimal, hindering their practical applications. Herein, we present a high-performance, highly flexible MEG achieved by integrating reduced graphene oxide (rGO) nanosheets and LiCl into a polyacrylamide (PAM) hydrogel matrix (namely PGL). The rGO nanosheets serve as conductive nanochannels that facilitate rapid ion transport and charge redistribution, synergizing with hygroscopic LiCl to boost output. By combining experiments, molecular-level simulations, and theoretical modeling, we establish rational and robust design principles for the intricate electricity generation process governed by chemicalmass transport-electric coupling, effectively guiding device design and enabling performance prediction. The resulting MEG unit achieves a superior open-circuit voltage of 0.6 V and a short-circuit current of 0.58 mA/cm 2 , which previously required hundreds of MEGs connected in parallel. Notably, our MEG banks connected in series and parallel are demonstrated to power wearable devices with integrated electronics. This work highlights a significant advancement in the design and scalability of MEGs, paving the way for their integration into flexible electronics and wearable technologies.