An Adaptable Charge Source Enabled by Mode‐Switchable TENG for Efficient Self‐Repairing Coating

Abstract Self‐repairing coatings have received widespread attention due to their ability to repair damaged surfaces. However, film‐forming molecules can only be fixed on the metal surface through relatively weak physical and chemical adsorption. This drawback limits its self‐repairing ability. Here, a mode‐switchable TENG (MS‐TENG) is developed, which has the ability to switch between AC and DC outputs as an adjustable charge source for self‐repairing coatings. Besides the normal sector electrodes of rotational TENG, MS‐TENG has a special design of external electrodes (small extension electrodes on rotator and inner/outer orbit electrodes on stator) and achieves charge accumulation through an excitation circuit and DC output through air breakdown on external electrodes with advantage of the complete release of accumulated charges. Compared with traditional air breakdown TENG, its current output has been improved. In addition, the air breakdown process occurs in the external electrode framework independent of the TENG body. Therefore, the negative impact of air breakdown is suppressed. Finally, MS‐TENG is used to achieve rapid electrostatic adsorption of charged film‐forming molecules through charge injection. MS‐TENG as a charge source effectively improves the performance of self‐repairing coatings, with a corrosion inhibition rate of 96.9%.