A Bilayer Hydrogel with Heterogeneous Structures for Highly Efficient Moisture Energy Harvesting

Moist-electric generators (MEG), which extract energy from ambient moisture, offer a potential solution to the escalating energy crisis. However, current MEG technologies encounter significant challenges, including pulsed output and limited power generation capacity. In this study, a heterogeneous hydrogel-based MEG (H-MEG), incorporating both hydrophilicity and double ion concentration gradients, was developed. A single H-MEG device (1 × 1 cm2) achieved a maximum open-circuit voltage (VOC) of 0.64 V and a short-circuit current (ISC) of 72.12 μA at 80% relative humidity. Furthermore, by employing series and parallel integration of H-MEG banks, enhanced performance was achieved with voltages of 6.62 V and currents of up to 670.86 μA, respectively. These scalable H-MEG devices could directly power commercial electronic devices, including light-emitting diodes and commercial calculators. This study proposes a cost-effective and highly efficient approach for harvesting electricity from moist air, significantly contributing to the advancement of green power sources.