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.

URL: https://advanced.onlinelibrary.wiley.com/doi/10.1002/adfm.202425225