Leaf‐Like TENGs for Harvesting Gentle Wind Energy at an Air Velocity As Low As 0.2 M S−1

Existing technologies for harvesting electrical energy from gentle wind face an enormous challenge due to the limitations of cut-in and rated wind speed. Here, a leaf-like triboelectric nanogenerator (LL-TENG) is proposed that uses contact electrification caused by the damped forced vibration of topology-optimized structure consisting of flexible leaf, vein bearing plate, and counterweight piece. The effectiveness of the topology-optimized leaf-like structure is studied, which solves the problem of reduced output due to electrostatic adsorption between the leaf surfaces while reducing the cut-in (0.2 m s(-1)) and rated wind speed (2.5 m s(-1)). The LL-TENG unit having small dimensions of 40 cm(-2) (mass of 9.7 g) at a gentle wind of 2.5 m s(-1) exhibits outstanding electrical performances, which produces an open-circuit voltage of 338 V, a short-circuit current of 7.9 mu A and the transferred charge density of 62.5 mu C m(-2) with a low resonant frequency of 4 Hz, giving an instantaneous peak power of 2 mW. A distributed power source consists of the five LL-TENGs in parallel is developed by designed self-adaptive structure, for which the peak power output reaches 3.98 mW, and its practicability and durability are successfully demonstrated. This study is a promising distributed power source technology to drive electronics in gentle wind outdoor environments.