Fabrication of Electrospun PAN–CNT–CNC Composite Nanofiber Films for Hydrovoltaic Energy Harvesting

Water-induced electrical responses were investigated using porous electrospun PAN-based composite membranes containing CNTs and CNCs. Following the injection of 20 μL of a 2 wt% NaCl solution, transient open-circuit voltage responses were observed from the PAN, PAN–CNT, and PAN–CNT–CNC devices, with maximum values of approximately 47, 42, and 68 mV, respectively, in the tested devices. Three successive injection–drying cycles demonstrated repeated transient responses within individual devices but did not establish device-to-device reproducibility or long-term stability. Raman and FTIR analyses supported the incorporation of CNTs and the modification of the water-interacting environment following CNC addition, respectively. The voltage waveform depended on the liquid type, NaCl concentration, and wetting–drying history, including a transient reverse-voltage response during drying. These results provide a proof-of-concept observation of wetting–drying-dependent electrical behavior in electrospun PAN-based porous membranes. Load-dependent power, long-term durability, and device-to-device reproducibility remain to be established.