Zinc Oxide-Enhanced Piezoelectret Polypropylene Microfiber for Mechanical Energy Harvesting

This paper reports zinc oxide (ZnO)-coated piezoelectret polypropylene (PP) microfibers with a structure of two opposite arc-shaped braces for enhanced mechanical energy harvesting. The ZnO film was coated onto PP microfibers via magnetron sputtering to form a ZnO/PP compound structure. Triboelectric Nanogenerator (TENG) based on ZnO/PP microfiber compound film was carefully designed with two opposite arc-shaped braces. The results of this study demonstrated that the mechanical energy collection efficiency of TENG based on piezoelectret PP microfiber was greatly enhanced by the coated ZnO and high-voltage corona charging method. We found that, with the step-increased distance of traveling for the movable carbon black electrode, an electrical power with an approximately quadratic function of distance was generated by this mechanical-electrical energy conversion, because more PP microfibers were connected to the electrode. Further, with a full contact condition, the peak of the generated voltage, current, and charges based on the ZnO/PP microfibers by this mechanical-electrical energy conversion with 1 m/s² reached 120 V, 3 μA, and 49 nC, respectively. Moreover, a finger-tapping test was used to demonstrate that the ZnO/PP microfiber TENG is capable of lighting eight light-emitting diodes.