Regulating Electrostatic Discharge via Quasi-gate Electrode for High-Performance Direct-current Triboelectric Nanogenerators.

Abstract

Direct-current triboelectric nanogenerators (DC-TENGs) are promising for mechanical energy harvesting but are often hindered by incomplete charge collection and parasitic discharge pathways. Herein, inspired by the operating characteristics of depletion-mode field-effect transistors, we propose a quasi-gate-electrode enhanced DC-TENG (QGED-TENG). The QGED-TENG employs a back-side quasi-gate-electrode (QGE) and porous polytetrafluoroethylene film to modulate electrostatic breakdown and charge leakage, thereby effectively suppressing parasitic discharge. The QGED-TENG enables direction-contingent enhancement and depletion modes without external bias, notably delivering a 1.41-fold output charge increase in enhancement mode compared to the device without the QGE. Furthermore, by leveraging redistributed electric fields and parallel discharge pathways, the multi-unit architecture achieves a linear charge increase relative to the number of units. Benefiting from the synergistic effects of electrostatic breakdown, charge leakage, and electric field redistribution within the multi-unit configuration, an optimized rotational QGED-TENG achieved an ultrahigh average power density of 25 W m^-2 Hz^-1 and an output charge density of 13.65 mC m^-2 at 60 rpm, setting a new benchmark for the porous triboelectric layer of electrostatic breakdown-based DC-TENGs. This work provides new physical insights and a general design strategy for maximizing spatial charge utilization and enabling high output performance DC-TENG.