Flexible Piezoelectric Nanogenerator Based on a Poly(vinylidene fluoride)–Ti₃C₂ MXene Film for Underwater Energy Harvesting

The goal of energy harvesting is to create self-powered devices that can operate without the need for batteries or external power sources. This research intends to synthesize, characterize, and develop a flexible piezoelectric polymer composite device of poly(vinylidene fluoride) (PVDF) and Ti3C2 using a simple solvent-casting approach without an external poling procedure. Nanocomposites of PVDF with different concentrations of MXene (0.2, 0.8, 1, and 2 wt %) are prepared by the solvent-casting method using DMF as a solvent. Addition of Ti3C2 nanosheets into the polymer matrix has enhanced the β phase content in PVDF. PVDF added with 1 wt % MXene exhibited the highest β phase percentage as well as improved piezoelectric properties. Because MXene is distributed evenly in the PVDF matrix, it improves the β phase of PVDF while decreasing the undesirable α phase configuration. According to the data obtained from dynamic contact electrostatic force microscopy, 1 wt % MXene-incorporated PVDF has a greater voltage output than other PVDF–MXene compositions. The ATR-IR spectrum reveals that the β phase has been improved. A piezoelectric nanogenerator was fabricated with the composition of PVDF–1 wt % MXene. The device is tested by finger tapping which produces an electrical output of 5 V. The underwater energy-harvesting experiments were performed with different water flow rates from 0 to 3 m/s. The output voltage increased with water flow rate to a maximum peak-to-peak voltage of 21 V at a water flow rate of 3 m/s with a short-circuit current of 0.9 μA. The device can be used to power underwater sensor networks.