Quantifying contact status and the air-breakdown model of charge-excitation triboelectric nanogenerators to maximize charge density

Yike Liu,Zhao Wang,Hengyu Guo,Hengyu Guo,Wenlin Liu,Yi Xi,Chenguo Hu,Qian Tang,Wencong He,Xue Wang

doi:10.1038/s41467-020-15368-9

Yike Liu, Zhao Wang + Show 8 more

Open Access

https://doi.org/10.1038/s41467-020-15368-9

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Abstract

Surface charge density is the key factor for developing high performance triboelectric nanogenerators (TENG). The previously invented charge excitation TENG provides a most efficient way to achieve maximum charge output of a TENG device. Herein, criteria to quantitatively evaluate the contact efficiency and air breakdown model on charge excitation TENG are established to enhance and evaluate charge density. The theoretical results are further verified by systematic experiments. A high average charge density up to 2.38 mC m−2 is achieved using the 4 μm PEI film and homemade carbon/silicone gel electrode in ambient atmosphere with 5% relative humidity. This work also reveals the actual charge density (over 4.0 mC m−2) in a TENG electrode based on quantified surface micro-contact efficiency and provides a prospective technical approach to improve the charge density, which could push the output performance of TENG to a new horizon.

Highlights

Surface charge density is the key factor for developing high performance triboelectric nanogenerators (TENG)
Surface charge density is the key factor for improving the output performance of a TENG device
The actual charge density in charge-excitation TENG (CE-TENG) is over 4.0 mC m−2, which means that the maximum output charge density could be up to 4.0 mC m−2 in an ideal surface contact level

Summary

Introduction

Surface charge density is the key factor for developing high performance triboelectric nanogenerators (TENG). In contact-separation mode TENG, derived from Paschen’s law and TENG parallel-plate model, the effect of dielectric parameters and atmospheric environment on maximum surface charge density under short-circuit condition has been well expounded[16,17]. Surface charge density can be improved by the above strategies, for a common TENG device, the surface charge generated by contact electrification is usually far below the maximum one due to the lack of surface electro-states (electron cloud overlap on the contact interfaces)[16] In this case, surface modification using physical/chemical methods[21,22,23,24], is always adopted for achieving a larger charge output to approach the maximum value. The higher average charge density is hardly obtained due to the insufficient contact

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