Ultrahigh charge density realized by charge pumping at ambient conditions for triboelectric nanogenerators

As a promising technology to harvest mechanical energy from environment, triboelectric nanogenerators (TENGs) impose great importance to further enhance the power density, which is closely related to the charge density on the dielectric surface. A few approaches have been proposed to meet the challenge to improve the charge density, while certain preconditions restrict their applications. Here, a facile and universal method using floating layer structure and charge pump is proposed, based on which an integrated self-charge-pumping TENG device is fabricated. The device adopts a floating layer to accumulate and bind charges for electrostatic induction, while a charge pump is devised to pump charges into the floating layer simultaneously. With elaborately designed structures, this device can achieve ultrahigh effective surface charge density of 1020 mu C m(-2) in ambient conditions, which is 4 times of that of the density corresponding to air breakdown, presenting a simple and robust strategy to greatly enhance the output of TENGs which should be crucial for developing high performance energy harvesting devices and self-powered systems.