Controllable Core–Shell BaTiO3@Carbon Nanoparticle-Enabled P(VDF-TrFE) Composites: A Cost-Effective Approach to High-Performance Piezoelectric Nanogenerators

Piezoelectric nanogenerators (PENGs), as a promising solution to harvest mechanical energy from ambient environment, have attracted much attention over the past decade. Here, the core–shell structured BaTiO3@Carbon (BT@C) nanoparticles (NPs) were synthesized by a simple surface-modifying method and then used to fabricate the efficient PENGs with poly[(vinylidene fluoride)-co-trifluoroethylene] (P(VDF-TrFE)). The carbon shell with the uniform thickness of 10–15 nm can increase the content of the polar β phase in P(VDF-TrFE) and significantly enhance the interfacial polarization between BT NPs and the polymer matrix during the poling process. Out of all compositions, the 15 wt % BT@C/P(VDF-TrFE) PENG exhibited the optimal piezoelectric performance with an output voltage of ∼17 V and a maximum power of 14.3 μW under bending–releasing mode. More importantly, the PENG can also efficiently harvest other types of mechanical energy from human activities and exhibits stable output after 1500 bending–releasing cycles. When the PENG was bent and beat by bicycle spokes, a peak voltage of 16 V was generated, which can light up 12 white LEDs directly and charge the commercial capacitors. Our research provides a new strategy to fabricate flexible and efficient PENGs from a nanoscale viewpoint; it can be hopefully applied in energy-harvesting systems and wearable electric sensors.