Development of an efficient, lead-free piezoelectric nanogenerator utilizing PVDF: MnO2–Bi2WO6: RGO composite fiber for self-powered sensing and biomechanical energy harvesting

In this study, we have fabricated a highly efficient, environmentally safe, and flexible piezoelectric nanogenerator (PENG) utilizing a composite material comprising manganese oxide-bismuth tungstate (MnO₂–Bi₂WO₆), polyvinylidene fluoride (PVDF), and reduced graphene oxide (RGO) by an optimized electrospinning technique. The PENG constructed with aluminum-based electrodes demonstrates an open-circuit voltage of 5 V and a short-circuit current of 2 μA under the influence of a compressive force measuring 10 N at a frequency of 3 Hz. These measurements were 3.2 and 3.3 times higher, respectively, than those of the original PVDF PENG. Moreover, the optimized PENG achieved an instantaneous power density of 0.4 mW. The exceptional performance of the nanogenerator can be ascribed to the synergistic blend of the β-phase PVDF polymer, the non-centrosymmetric characteristics of MnO₂–Bi₂WO₆ nanosheets, and the electrical conductivity provided by RGO. Additionally, to evaluate both its capacity for sensing and energy harvesting capabilities, the fabricated PENG was utilized for detecting diverse human movements and charging multiple capacitors. Observations revealed that mechanical stimulation could charge a capacitor with a capacity of 1 μF–5 V within 2.4 s, suggesting a viable platform for removing the requirement of an external power source for operating portable devices. As a result, the created PENG exhibits considerable promise and can serve as a viable substitute for traditional power sources in self-sustaining devices, providing its stability and flexibility.