Surface Charge‐Engineered Activated Carbon‐PVDF Composite‐Based Thin Film Device for Hydrovoltaic Applications

ABSTRACT This study introduces a thin‐film‐based hydrovoltaic electricity generator under ambient conditions with low mass loading. A novel design based on the development of a low‐cost, high‐performance hydrovoltaic power generator utilizing a composite material based on bio‐derived activated carbon (AC) and polyvinylidene fluoride (PVDF) has been proposed. The PVDF was incorporated to leverage its ability to enhance the electronegativity of the material upon interaction with solvents and acts as a binder, thereby inducing a hydrovoltaic effect despite its hydrophobicity. By optimizing the weight ratio of PVDF with AC, the resulting device successfully delivered a peak output of above 1 V and an average current of 50 µA and demonstrates a maximum power output of 14 µW/cm 2 . Simultaneously, the generated power can be maintained by dropping a single drop of water on top of the device after an optimized amount of time. The device exhibited the crucial capability to resume power output after 60 days of idleness under ambient humidity and temperature conditions, underscoring its potential for practical and real‐time applications. Furthermore, the integration of a supercapacitor in the same device is also tested for obtaining an increased current output.