High-Efficiency Charge Injection with Discharge Mitigation Strategy for Triboelectric Dielectric Materials

The high surface charge density of triboelectric dielectric materials is the core of high output performance triboelectric nanogenerators (TENGs). However, the increase in surface charge density enabled by the existing triboelectric material modification is still far from the saturation value (& sigma;(BS)) limited by air breakdown. Here, utilizing the directional high electric field generated by the charge excitation technology of the voltage-multiplying circuit, an ultrafast charge self-injection strategy is proposed. An ordinary contact-separation TENG with a working frequency of 1.5 Hz can realize charge self-injection on the surface of its dielectric layer to a saturation value within 22 s. Furthermore, the surface charge on the dielectric layer after excessive charge self-injection can be retained to the maximum value by the step-by-step discharge mitigation strategy. Finally, by using a 7 & mu;m thick polyimide film, a super-high charge density of 1480 & mu;C m(-2) is achieved after charge injection, which is the historical high by modification of single layer material series currently. The charge self-injection technology combined with discharge mitigation strategy proposed in this work is an important breakthrough in the field of triboelectric layer modification. In addition, this work also provides a systematic discussion on the & sigma;(BS) of dielectric layer related physical mechanism.