Interface Induced High-Performance Piezoelectric Nanogenerator Based on a Electrospun Three-Phase Composite Nanofiber for Wearable Applications

Polymer based composites are the backbone of piezoelectric flexible devices, but the use of toxic compounds or requirement of high voltage poling are the Achilles’ heel of this field. Herein, a lead-free, self-poled, flexible, high performance piezoelectric nanogenerator (PENG) is demonstrated based on a poly(vinylidene fluoride) (PVDF)–ZnSnO3–MoS2 free-standing electrospun nanofiber mat. ZnSnO3 and MoS2 were synthesized by a hydrothermal route, and a composite nanofiber mat was prepared by the electrospinning method. The structural study revealed an enhancement of the electroactive β-phase of PVDF due to inclusion of MoS2. With the optimized concentration of MoS2, the fabricated piezoelectric device can generate open-circuit voltage, short circuit current, and an instantaneous power density of 26 V, 0.5 μA, and 28.9 mW m–2, respectively, with gentle finger tapping. This power density is almost 18 times more than that of PENG made out of pristine PVDF, and the enhancement in the performance is attributed to the synergistic effect of interfacial action due to the piezoceramic (ZnSnO3) and MoS2 in the PVDF matrix. Both ZnSnO3 and MoS2 interact with −CF and −CH dipoles of PVDF to mobilize the bonds to enhance the electroactive phase of PVDF. Biomechanical energy harvesting, sensing of movement of different body parts, and real-time application such as charging capacitors and powering a calculator were demonstrated using the as-fabricated nanogenerator. The device showed reliable performance when tested for 3000 cycles and durability over 50 days of storage. This superior performance and robustness of the device make the PVDF–ZnSnO3–MoS2 based electrospun nanofiber mat an ideal candidate for energy harvesting and sensing applications.