Polymer-biofilm interface enables exceptional hydrovoltaic electricity generation.

Abstract

Sustainable hygroelectricity generation has emerged as a revolutionary technology capable of harvesting the latent heat from ambient environments and converting it into direct-current electricity. Recently, microbial biofilms have been regarded as promising hydrovoltaic materials for their low-cost, facile fabrication and environmentally friendly nature. However, external moisture dependence and ultra-high internal resistance have greatly limited the output performance of microbial biofilm-based hydrovoltaic electricity generators (BioHEGs). Herein, a core@shell structured biohybrid system (S. o@PPy) was constructed by in situ polymerization of pyrrole monomers on the surface of Shewanella oneidensis (S. o) cells. The presence of polymer-biofilm interfaces resulted in a remarkable performance of hygroelectricity generation originated from the built-in conductivity of hole-doped polypyrrole (PPy), as well as the reduced internal resistance and improved water adsorption capacity of S. o biofilms. Hence, the S. o@PPy BioHEG generated a stable short-circuit current of ca. 33.5 μA at the optimal condition, which is significantly higher than all BioHEGs documented hitherto. Moreover, a novel mechanism of asymmetric charge redistribution was confirmed by density functional theory (DFT) calculations. These results support a new perspective of hydrovoltaic effects and provide a viable strategy for advancing BioHEGs towards more practical scenarios such as humidity sensing and electronic power supply.

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