Evaporating potential

Summary

The conversion of ambient heat into electricity through ubiquitous natural evaporation offers hope for new green energy technologies. So far, evaporation-induced electricity has relied mainly on the classical streaming potential, which is an electric potential generated by driving an electrolyte through a narrow channel under a pressure gradient. Here, we show that evaporation of ethanol from nanostructured carbon films can produce a sustainable volt-level potential in an environment free from the streaming potential, which we term the evaporating potential. This evaporating potential is proven to occur within a narrow partially wetted region ahead of the main capillary film and is directly generated by carrier transfer driven by evaporation of ethanol molecules. It is also shown that other polar solvents can generate potentials comparable to those induced by ethanol. The finding could open a new way to harvest environmental energy through natural processes.