An Ultrafast Self-Polarization Effect in Barium Titanate Filled Poly(Vinylidene Fluoride) Composite Film Enabled by Self-Charge Excitation Triboelectric Nanogenerator

摘要

Although charge excitation is an effective approach to achieve high chargedensity for triboelectric nanogenerators (TENGs), high output charge islimited by air-breakdown. Due to capacitor structure, there are two ways toreduce the influence of air-breakdown in TENG: decrease in thickness andincrease in permittivity of dielectric film. Obviously, the increase in permittivityis more reliable in applications. Herein, a double-layer TENG sharedwith one floating metal electrode is proposed, on which charge is injectedby a self-excitation circuit. An ultrafast self-polarization effect is found in twobarium titanate filled poly(vinylidene fluoride) composite films in the TENGby high electrical field produced from the floating electrode. According tocomparison and analysis, the speed of polarization to saturation of dielectriccomposite films in self-charge excitation approach is ≈3 times faster than thatof external-charge excitation. Optimization of various parameters is investigatedto enhance the output performance of the TENG. A large output chargedensity of 1.67 mC m~(–2) is achieved in the atmosphere with 40% relativehumidity due to self-polarization effect of the dielectric composite film. Thisstudy provides insights into understanding the polarized behavior of moleculesin dielectrics and further optimizing the output performance of TENGsin self-charge excitation systems.