Recursive Charge Feedback for Fast-Response Triboelectric Nanogenerators with Predictive Design

Abstract

Start-up delay under intermittent, low-frequency motion limits triboelectric nanogenerators (TENGs) as practical power sources for battery-free devices. This work reports a charge-feedback TENG (CF-TENG) that recursively injects its own output charge to the opposite TENG's electrode and establishes a positive-feedback loop that strengthens the internal electric field. The architecture delivers kilovolt-class open-circuit voltages within tens of seconds under sub-Hz irregular excitation and reduces start-up time by orders of magnitude relative to half-wave-rectified and charge-excitation designs. Model-experiment agreement confirms the mechanism and guides a polarity-aware topology that maximizes constructive charge accumulation. To ensure a stable feedback loop, we devised a material-selection protocol that evaluates charge-retention capability under controlled potential-conditioning cycles, and we identified materials that sustain induced surface potential within repeated feedback operations. A large-area CF-TENG achieved rapid voltage build-up to +/- 6 kV in bipolar mode and 14 kV in unipolar mode without external charge storage. The study advances TENG evaluation toward time-response metrics such as start-up time, saturation time, and average charging speed, and establishes actionable design rules that link material choice and feedback topology. The recursive charge-feedback strategy enables fast-starting, battery-free energy harvesting for self-powered sensors and wearables and strengthens the case for TENGs as sustainable power solutions.