Rapid room-temperature preparation and hydrovoltaic application of biohydrogel

<p indent="0mm">Evaporation-induced electricity is a hydrovoltaic technology that uses water evaporation to generate electricity, and has attracted attention due to its highly self-generating and sustainable electricity production capability. Hydrogels, which are rich in hydrophilic functional groups and have good water transport properties, are considered as promising functional materials for evaporation-induced electricity generation. However, the preparation of traditional hydrogels usually requires heating or ultraviolet-induced polymerization, which is a complicated and time-consuming process, severely limiting the practical application of hydrogel-based hydrovoltaic technology. Herein, <italic>Geobacter sulfurreducens</italic> (<italic>G</italic>.<italic> s</italic>) was used as a model microorganism to induce the rapid polymerization of nanocellulose and polyacrylamide macromolecular chains at room temperature, which resulted in the synthesis of a biohydrogel film with excellent performance within one minute. The abundance of reducing functional groups in <italic>G</italic>.<italic> s</italic> reacted with S₂O₈²⁻ in a spontaneous redox reaction, releasing heat and free radicals, which accelerated the polymerization reaction. Owing to the excellent electrical conductivity of <italic>G</italic>.<italic> s</italic>, the <italic>G</italic>.<italic> s</italic> biohydrogel film has both excellent charge transfer capability and mechanical properties, which is beneficial for the application of aqueous hydrovoltaic devices. The evaporation generator assembled by <italic>G</italic>.<italic> s</italic> biohydrogel film can output <sc>~13 μA</sc> of current for a long time, which can be used to power small electronic devices. In conclusion, the present study provides an energy-saving, simple, and rapid method for the preparation of biohydrogel film, which provides a new choice for the key functional materials of hydrovoltaic technology and practical application.