Synergistic electrospinning-electrospraying process to fabricate oxidized carbon nanotubes/polyacrylonitrile fabric for evaporation‐induced electricity generator

The evaporation-induced electric generator (EIG) based on the hydrovoltaic effect is a sustainable energy harvester that converts the phase-change energy of water into electricity through interactions between functionalized nanomaterials and water molecules. However, the complex processes and low cost-effectiveness of most hydrovoltaic materials hinder the further large-scale application of the EIGs. In this study, the polyacrylonitrile (PAN) nanofibers and oxidized carbon nanotubes (O-CNTs) are combined through an electrospinning-electrostatic spraying synergistic process to obtain a flexible O-CNTs/PAN composite nanofiber membrane, and an EIG device is constructed using the membrane. The three-dimensional interconnected porous network structure of the nanofibers provides effective water transportation channels, and the O-CNTs on the surface of PAN contain a large number of oxygen-containing groups, which undergo electrostatic bonding with protons or metal ions. The optimized device achieves a stable open-circuit voltage of 0.18 V. With a 2 wt% sodium chloride (NaCl) solution, the device exhibits a peak short-circuit current ( I SC ) of 14.2 μA. Through the integration of multiple EIG units, a module powers small electronic components. This study provides a cost-effective and easy-scalable strategy for the design and construction of efficient hydrovoltaic devices, providing valuable references for the large-scale application of EIGs. • A scalable one-step strategy for fabricating composite fibers is developed. • A water-evaporation-induced generator (OCP-EIG) is constructed from this membrane. • OCP-EIG provides a stable voltage for over 30 h under indoor conditions. • OCP-EIG achieves a 14.2 μA short-circuit current in 2 wt% NaCl solution.