Excellent triboelectric properties of P(VDF-TrFE) nanofibers incorporated with Bi-based oxide-modified KNN polycrystals

Recently, improving triboelectric nanogenerator (TENG) performance with inorganic nanofillers and crafting multifunctional nanofiber films via electrospinning have gained much attention. This paper explores the effect of electrospun composite nanofibers based on P(VDF-TrFE) (denoted as PT) with K0.5Na0.5NbO3 (KNN) polycrystals doped with bismuth-based (Bi-based) oxides [Bi(Ni0.5Hf0.5)O3 (BNH) and Bi(Mg0.5Zr0.5)O3 (BMZ)] on the output performance of TENG. TENGs with four types of [PT-PET, (PT/KNN)-PET, (PT/KNN-BNH)-PET, and (PT/KNN-BMZ)-PET] are compared, and the output increases progressively from pristine (Voc = 572 V and Isc = 13.4 μA) to PT/KNN-BMZ (Voc = 831 V and Isc = 39.2 μA). The maximum output performance is higher than that of most previously reported inorganic particle-modified films. Electrospinning provides a high applied voltage, enhancing dipole alignment, which aids in the formation of the β-phase. Additionally, modifying KNN ceramics with BNH and BMZ and using them as nano-fillers not only increases the β-phase of P(VDF-TrFE) but also elevates its dielectric constant, enhancing the capacitance of TENG, thereby yielding superior triboelectric performance. Furthermore, when different KNN/BMZ concentrations are compared, the (PT/4% KNN-BMZ)-PET TENG demonstrates the optimum triboelectric output performance, with 13.84 mW of peak power at a matched load of 40 MΩ. This work provides guidance for nanofiller choices for high-performance TENG preparation.