Hybrid Fillers ofBarium Titanate and FunctionalizedMulti-Walled Carbon Nanotubes Incorporated Poly(vinylidene fluoride)Nanocomposites for Piezoelectric Nanogenerators

Flexible energy harvesters with great performance have recently received a lot of attention due to their enormous potential for creating fully flexible self-powered devices. In this study, we have fabricated flexible piezoelectric nanogenerators (PENGs) using the hybrid fillers of different weight ratios of barium titanate (BaTiO₃) and functionalized multiwalled carbon nanotubes (f-MWCNTs) in the PVDF matrix. Morphological and structural examinations of the nanocomposites revealed the extended fibrillar-type characteristics originating from the β-crystalline phase of PVDF, which improved the output performance of PENGs. PVDF/BaTiO₃/f-MWCNT nanocomposites showed outstanding characteristics enabling them to have ∼94% electroactive phase, making them excellent for piezoelectric energy harvesting devices. The inclusion of the hybrid fillers of BaTiO₃/f-MWCNTs into the PVDF matrix dramatically improved the dielectric, ferroelectric, and output performance of PENGs. An optimized composition of PVDF nanocomposite of the hybrid fillers weight ratios of 1:1 (PBC11) having 1.5 wt % hybrid fillers, and 1:2 (PBC12) having 0.75 wt % hybrid fillers exhibited an output power density of ∼55 and ∼45 μW cm^–2, a higher open-circuit voltage of ∼69 and ∼63 V, and a short-circuit current of ∼2.34 and ∼2.31 μA, respectively, exhibiting sufficient capabilities to power small portable electronics. The device proved to be highly sensitive and effective when subjected to biomechanical forces. In addition, the PENGs could evaluate the exercise status and hand fatigue of rehabilitation trainers and the elderly persons in real time, as well as monitor fingers flexibility and strength. By expanding the field of flexible and wearable electronics, the PENG device represented a noteworthy turning point in human–machine interactions.