Cellulose/ionic hydrogel moisture electric generators with enhanced output and stability

Harvesting energy from ubiquitous moisture in air from the interaction with hygroscopic materials shows great promise in green energy and portable power for off-grid electronics. However, the lack of efficient materials design and tunable ions migration result in the short duration time and low output. Here, we propose an efficient and durable moisture electric generator (MEG) design by adding cellulose nanofibers into ionic hydrogel where sodium ions act as anchors through electrostatic interactions to prevent the output collapse. The accessible nanochannels in cellulose nanofiber clusters provide the additional ion migration pathways for efficient electricity generation. A single MEG device can yield open-circuit voltage of 0.8 V and maintain >95 % of its initial output even after ∼1000 h of continuous operation. This maintaining period exceeds the operating time of similar devices by a factor of 10–60. Importantly, this long duration is purely originated from the intrinsic moisture electricity generation since the utilization of inert electrodes in MEGs eliminates the potential chemical reactions between water and the electrodes. Our work presents a strategy for designing intrinsically sustainable MEGs with enhanced output and paves ways for achieving substantial breakthroughs for moisture power generation.