Charge pumping triboelectric metamaterials with capacitor-enabled multifunctionalities

Abstract

Most traditional triboelectric nanogenerators (TENGs) feature alternating current (AC) output and cannot be directly utilized as a power source to charge energy storage systems or drive direct current (DC) electronic devices. Converting AC into DC typically requires stiff and complicated rectifier bridge circuits, which hinders TENG’s integration into rationally designed flexible three-dimensional architectures to construct all-in-one energy harvesting-storing multifunctional metamaterials. Herein, triboelectric metamaterial (TM) with a charge pumping mechanism is developed to harvest energy from linear mechanical motions and generate DC output. The TM incorporates a capacitor composed of negative electrodes and an assistant electrode for charge storing and charge transfer boosting. Under open-circuit conditions, triboelectric charges are sustainably accumulated and stored within all the electrodes. With the extra charge storage of the capacitor formed by the negative electrode and the assistant electrode, the TMs’ charge-storing capability can be enhanced by 203 %. Moreover, the accumulated charges in the assistant electrode during open-circuit energy harvesting amplify the short-circuit charge output by 55.6 % through electrostatic induction. TM’s inner part can serve as a portable power source storing the harvested electricity independently upon completion of the TM’s open-circuit energy harvesting. In addition, the TM can detect the proximity of charge-carrying objects by monitoring fluctuations in open-circuit voltage over time. The seamless integration of charge pumping, energy storing, and sensing functionalities offered by the TMs imparts paradigm shifts in energy harvesters to be applied as portable green power sources and self-sensing intelligent suspension systems.