Improved Output Performance of Direct‐Current Triboelectric Nanogenerator through Field Enhancing Breakdown Effect

Abstract The emerging direct‐current triboelectric nanogenerator (DC‐TENG) does not need to be rectified and is not restricted by a dielectric breakdown compared with an alternating current TENG (AC‐TENG). Furthermore, the charge density of the DC‐TENG reaches an ultrahigh level far beyond that of the AC‐TENG based on a rational design. However, there are always some electrons remaining on the surface of the dielectric after the breakdown process in the DC‐TENG, and therefore a low charge utilization is obtained. Herein, a simple and universal method is proposed through a double‐layer structure design, that is, a triboelectric layer as the friction layer and an electret layer charged through a surface treatment as the field‐enhancing layer to further improve the output performance of the DC‐TENG, which is inspired by the fable “The Crow and the Pitcher.” Owing to the external field‐enhancing breakdown effect, a double improvement in the breakdown efficiency and output charge density is obtained compared with a conventional DC‐TENG. Moreover, a nearly constant output current has been demonstrated for directly powering electronics without a rectifier. This study provides a universal method for optimizing the output performance of a DC‐TENG.