Long‐Lasting and Steady Triboelectric Energy Harvesting from Low‐Frequency Irregular Motions Using Escapement Mechanism
Kwan‐Woo Han, Jong‐Nam Kim, Araz Rajabi‐Abhari, Van‐Tien Bui, Ji‐Seok Kim, Dukhyun Choi, Il‐Kwon Oh
Abstract
Abstract Most mechanical energy harvesters produce only small amounts of electrical power from extremely low‐frequency input motions and immediately stop generating electricity when mechanical kinetic energy is exhausted. Here, a steady, long‐lasting and power‐boosted triboelectric nanogenerator is reported that can efficiently harvest from extremely low‐frequency irregular motions of less than 0.1 Hz by utilizing an escapement mechanism and frequency up‐conversion device. The escapement mechanism‐based triboelectric nanogenerator (EM‐TENG) consists of a mechanical energy storage spring, escapement mechanism and a torsional resonator for regular operation and frequency up‐conversion. In addition, the micro‐patterned alternating dielectric surfaces of Nylon and polytetrafluoroethylene (PTFE) and the comb‐type rotator significantly improve the output performance of the rotational EM‐TENG, increasing the current density level approximately 4.2 times compared to flat surfaces. Under an input frequency of 0.067 Hz, the EM‐TENG produces an open circuit voltage of 320 V and a short‐circuit current density of 0.59 mA m ‐2 . Most importantly, the EM‐TENG can produce long‐lasting and steady output power for 110 s (22 times) under only 5 s of input motion. Therefore, the EM‐TENG might pave the way to effectively harvest energy from extremely low‐frequency motions in nature, such as human motion, structural vibration and ocean waves.