Osmotic Energy Conversion in Deep-Sea Hydrothermal Vents

Selective ion transport through nanochannels plays a crucial role in osmotic energy conversion in cellular systems. We show that this cell-essential process occurs in a submarine hydrothermal vent (HV) precipitate derived from a serpentine-hosted geological environment. Plate-like layered nanocrystals are aligned on the nano to millimeter scale, forming confined nanochannels in the HV precipitate. The nanochannels with surface charges function as a cation- and anion-selective ion transport membrane, allowing the precipitates to convert ionic gradients of Na+, K+, H+, and Cl- into electrical energy. Our findings suggest that osmotic energy conversion can occur spontaneously and widely through geological processes, offering valuable insights into the establishment of electrochemically coupled ion transport in early life as well as the creation of self-organized structures in engineering fields.