Constructing Water-Retaining/Ion-Regulating Bi-Layers for Highly Durable, All-Climate, Efficient Moisture Electric Generators.

Moisture electric generators (MEGs), which can directly convert chemical energy in moisture into electricity have demonstrated great potential for powering wearable electronics and IoT devices. However, state-of-the-art MEGs suffer from transient power output and rely on high relative humidity (RH) as well as mild temperature, hampering their practical applications. Herein, a novel high-performance MEG is reported by designing ionic hydrogel and graphene oxide dual-layered devices, where the water-enriched hydrogel enables continuous power outputs under various conditions while the inherent layering nanochannels effectively regulate ion diffusion for stable and efficient performance improvement. The MEG can generate a maximum power density of 71.7 µW cm and continuously output 0.6 V for more than 1400 h at room condition without degradation. Most importantly, the developed generator can operate well from -20 °C to 50 °C, and an ultrahigh and stable voltage of 1.2 V is realized at RH of 0% owing to the dynamic water equilibrium in the system. The MEG also displays excellent self-restoration capabilities, demonstrating high cyclic-performing potential. This work may provide important guidelines in designing long-life all climate applicable energy harvesting devices through designing synergistic bilayers architecture.