Multidimensional Nanochannel Regulation for High‐Performance Flexible Hydrovoltaic Sensing Devices

Abstract The evaporation‐induced hydrovoltaic effect represents a promising avenue for green energy harvesting and self‐powered ion sensing. However, the intricacies of designing the solid‐liquid interface and the insufficient systematic research on the influence of interface parameters on hydrovoltaic performance hinder the advancement of high‐performance hydrovoltaic devices. Herein, the governing principles of nanochannel size, material conductivity, surface properties, and water evaporation on the hydrovoltaic effect based on the multidimensional regulation of nanochannels by dip‐coating and carbonization processes are systematically elucidated. Guided by the obtained influence mechanisms, a high‐performance flexible hydrovoltaic sensing device with photothermal conversion capability is prepared, exhibiting an open‐circuit voltage exceeding 3.5 V and a wide univalent ion sensing range of 10 −7 –10 −1 m . Ultimately, the fabricated flexible hydrovoltaic device successfully serves for self‐powered electrolyte monitoring. These results systematically elucidate the correlation between the controllable design of solid–liquid interfaces (on structure, material conductivity, surface properties, and environmental factors) and high‐performance hydrovoltaic devices, paving the way for practical applications.