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.