Improving and Quantifying Surface Charge Density via Charge Injection Enabled by Air Breakdown

Abstract The modification of triboelectric materials is an important means to improve the output performance of triboelectric nanogenerator (TENG), and the surface charge or ion implantation is an effective way among many modification methods. However, the output enhancement via optimizing triboelectric materials is still limited. Herein, a fast surface charge injection technique based on air breakdown effect is reported, which utilizes an excitation circuit to realize the directional accumulation of charge. Consequently, the output charge density of the Polyimide (PI) film after charge injection reaches 880 µC m ‐2 , which is the highest of the series of modified triboelectric materials. Moreover, a novel charge transfer mechanism with electrostatic induction competition is proposed, in which significant difference between surface charge density and output charge density is highlighted clearly. Meanwhile, the method of quantifying surface charge density is further given. This work provides a more effective method for the modification of dielectric materials and also offers an important insight towards the charge transfer mechanism in TENG.