A facile and sustainable hygroelectric generator using whole-cell Geobacter sulfurreducens

Hygroelectric generator (HEG) technology based on ambient humidity is a promising self-sustained energy harvesting system, but it usually suffers from the disadvantages of expensive materials, complicated device construction processes, and unfavorable short-term power output. Herein, we propose a facile whole-cell HEG, which was fabricated from an easily prepared film of whole-cell Geobacter sulfurreducens (G.S.) and a low-cost indium tin oxide electrode. The HEG produced an open-circuit voltage of 0.3 V and a load current of 0.3 μA with a power density of 2.5 μW/cm2 that lasted for longer than 2160 h. The performance of HEGs constructed from G.S. nanowires (NWs), whole-cell G.S., and G.S.-without NWs was compared, which indicated that the energy harvesting behavior of the HEG was highly dependent on surface hydrophilicity and the ionization level, as determined by the content of hydrophilic groups in the film. Our results demonstrate a facile and inexpensive whole-cell HEG technology that generates sustainable hygroelectricity from ambient humidity. This development will greatly promote the practical application of hygroelectricity technology.