Scalable preparation of ultrathin porous polyurethane membrane-based triboelectric nanogenerator for mechanical energy harvesting

Scalable preparation of flexible, porous, and microstructure membrane for triboelectric nanogenerators (TENGs) with controllable thickness and high contact surface area using cost-effective methods is still a great challenge. Herein, we developed a novel, cost-effective, and scalable fabrication procedure for the preparation of a lightweight, flexible, thin, and porous polyurethane (PU) membrane for a TENG device. Importantly, the thickness and pore size of the PU membrane can be tuned easily. The PU-based TENG device fabricated with a porous PU membrane of 5 µm thickness and 15 µm pore size (PU-5-15) generated a maximum peak to peak output voltage was 58.5 V with a corresponding peak to peak current was 1.37 µA at 4 N and power density of 9.7 mW/m². The device was systematically used to energize 24 green commercial light-emitting diodes (LEDs) in brighter condition connected in series and to turn on the LCD of a portable timer clock within 51 s and glow for 1 s after 187 taps. The developed TENG device also exhibited stable cyclic charging and discharging property that is very important for real applications. Furthermore, the energy-harvesting performance of the device was also tested with human body movements. The developed industrially compatible method is very easy and convenient, and mass production is possible. Compared to other studies, in this novel study, we achieved a higher electrical performance at the desired lower thickness for the porous PU membrane-based TENG device. The developed fabrication method will pave the way for the facile and scalable industrial processing of PU membranes for energy-harvesting applications.