A Cylindrical Three-Dimensional Rotary Triboelectric Nanogenerator with Enhanced Contact Design for Mechanical Energy Harvesting

Rising interest in sustainable and self-powered electronic systems makes triboelectric nanogenerators a promising solution for harvesting ambient mechanical energy. This study proposes and investigates a cylindrical free-standing triboelectric nanogenerator (CF-TENG) to enhance energy conversion efficiency for self-powered systems. The device consists of a stator with interdigitated electrodes and a rotor with flexible blades coated by triboelectric materials. Performance was evaluated using different electrode materials (aluminum and polyamide-coated lacquered wire), triboelectric layers (Kapton and PTFE), and rotor blade configurations (double and quadruple) under various rotational speeds. The results show that both material selection and geometrical configuration strongly influence triboelectric output. PTFE outperforms Kapton in voltage and current generation due to its higher triboelectric charge density, while lacquered wire electrodes enhance charge generation compared to aluminum because of their higher electron affinity and enlarged effective contact area. The optimal configuration, consisting of quadruple PTFE-coated blades and lacquered wire electrodes, achieved 2086 V, 40 µA, and a peak power density of 5552.86 mW/m². Although increasing the blade number reduces rotational speed due to motor torque limits, it substantially improves energy harvesting. Capacitor charging tests confirm the capability of the proposed CF-TENG for efficient energy storage in practical low-power electronics.