Ion-electron coupling in a MXene/silk nanofluidic hydrovoltaic device for enhanced electricity generation

Abstract

Hydrovoltaic technology generates electricity directly via interactions between nanomaterials and water, demonstrating significant promise for sustainable energy harvesting. However, its widespread application is hindered by insufficient power output and poorly understood underlying mechanisms. Here, we develop a two-dimensional nanofluidic hydrovoltaic device using a MXene/silk nanoparticle composite membrane that leverages ion-electron coupling to enhance electricity generation. Upon deposition of deionized water droplets, an ionization-induced proton gradient generates a maximum open-circuit voltage of 496 mV and a peak short-circuit current of nearly 8 μA. Notably, replacing deionized water with 10-4 M NaCl elevates the output to 593 mV, which is further boosted to 622 mV under infrared irradiation—sufficient to power microelectronic circuits. Mechanism investigations reveal that this enhancement arises from ion-electron Coulomb drag interactions at the solid-liquid interface. This study provides fundamental insights into nanofluidic energy conversion and demonstrates potential applications in self-powered wearable electronics and all-weather energy harvesting systems.