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

Although charge excitation is an effective approach to achieve high charge density for triboelectric nanogenerators (TENGs), high output charge is limited by air-breakdown. Due to capacitor structure, there are two ways to reduce the influence of air-breakdown in TENG: decrease in thickness and increase in permittivity of dielectric film. Obviously, the increase in permittivity is more reliable in applications. Herein, a double-layer TENG shared with one floating metal electrode is proposed, on which charge is injected by a self-excitation circuit. An ultrafast self-polarization effect is found in two barium titanate filled poly(vinylidene fluoride) composite films in the TENG by high electrical field produced from the floating electrode. According to comparison and analysis, the speed of polarization to saturation of dielectric composite films in self-charge excitation approach is approximate to 3 times faster than that of external-charge excitation. Optimization of various parameters is investigated to enhance the output performance of the TENG. A large output charge density of 1.67 mC m(-2) is achieved in the atmosphere with 40% relative humidity due to self-polarization effect of the dielectric composite film. This study provides insights into understanding the polarized behavior of molecules in dielectrics and further optimizing the output performance of TENGs in self-charge excitation systems.

Automated summary

This study proposes a new double-layer TENG structure in which charges are injected through a self-excitation circuit and the breakdown of air is resisted by increasing the permittivity of the dielectric film. Experimental results show that the polarization rate of the dielectric composite film is approximately three times faster under the self-charge excitation approach compared to external-charge excitation. After optimizing various parameters, a high output charge density is achieved in an atmosphere with 40% relative humidity.