Interface induced performance enhancement in flexible BaTiO3/PVDF-TrFE based piezoelectric nanogenerators

Nanocomposites consisting of a flexible piezoelectric polymer and a reinforcing phase have shown great potential for constructing high-performance piezoelectric nanogenerators (PENGs). However, the weak interface and poor dispersion of piezoelectric reinforcing phase significantly impair the electromechanical properties (e.g. , effective stress/strain, piezoelectric coefficients) of the nanocomposites, thus severely restricting the performance enhancement of the PENGs. In this study, we hydrothermally synthesized the piezoelectric reinforcing phase of BaTiO 3 nanowires , and grafted a layer of high-modulus polymethyl methacrylate (PMMA) onto the nanowire surface via surface-initiated polymerization. The PMMA coating layer forms a strong interface between BaTiO 3 nanowires and the polymer matrix [i.e ., poly(vinylidenefluoride-co-trifluoroethylene)], which efficiently improves dispersion of the BaTiO 3 nanowires and stress transfer at the interface, therefore resulting in an enhanced output performance in the fibrous nanocomposite PENGs. The output voltage and current of the PMMA encapsulated BaTiO 3 (PMMA@BaTiO 3 ) nanowires-based PENG can reach to 12.6 V and 1.30 μA, with a maximum output power of 4.25 μW, which is 2.2 times and 7.6 times higher than the PENG with unmodified BaTiO 3 nanowires and the PENG without BaTiO 3 nanowires, respectively. Furthermore, the flexible PENG exhibits great stability that could continuously generate stable electrical pulses for 6000 cycles without any decline. This study provides a feasible approach of interface tailoring for achieving high-performance piezoelectric nanocomposite and shows the promising potential of the fibrous nanocomposites in biomechanical energy harvesters and smart wearable sensors.