Triboelectric horology: escapement-inspired design strategy for prolonged energy harvesting under irregular mechanical inputs

The intermittent nature of ambient mechanical energy sources such as wind, vibration, and human motion poses a significant challenge for the stable operation of triboelectric nanogenerators (TENGs). To address this issue, this study presents a long-lasting operable triboelectric nanogenerator (LONG), a novel TENG system that utilizes an escapement-based mechanical regulation strategy to convert irregular and low-frequency mechanical inputs into stable and continuous electrical outputs. LONG integrates a rotational TENG system and an escapement mechanism to achieve a controlled and unidirectional rotational motion, thereby prolonging the energy-harvesting duration while minimizing the energy losses due to torque fluctuation. A freestanding-mode TENG, enhanced with electret materials fabricated via corona discharge are adopted to ensure efficient charge induction under low-torque conditions. Parametric studies reveal that key design variables, including spring tension, gear ratio, electret surface potential, and applied mass, significantly influence the output stability and voltage amplitude. The optimized LONG system demonstrated a peak voltage of 300 V, a current of 19 μA, and continuous operation exceeding 3 min from a single winding. Furthermore, its ability to power 125 LEDs, a thermo-hygrometer, and a dust collecting system validates its practical applicability in self-powered systems. Thus, this study introduces a robust design framework for mechanical regulation in TENGs, offering a new pathway for stable energy harvesting from irregular mechanical sources for wearable, environmental, and infrastructure-monitoring applications.