Novel Flexible Friction Layer Constructed from ZnO In Situ Grown on ZnSnO3 Nanocubes Toward Significantly Enhancing Output Performances of a Triboelectric Nanogenerator

Material innovation plays an important role in improving the output performance of a triboelectric nanogenerator (TENG). In this work, a flexible ZnO@ZnSnO3/ZnSnO3/polydimethylsiloxane (PDMS) composite film is designed and prepared as the negative friction layer of TENG by a facile hydrothermal method based on in situ growth of the semiconductor ZnO on ferroelectric nanocubic ZnSnO3, which is lead-free and has a high dielectric constant, and cooperative uniform dispersion of nanoparticles. The effects of surface charge density, effective contact area, and interfacial polarization of the negative friction layer on the output performance of TENG are discussed experimentally and theoretically. Compared with the TENG involving pure PDMS, the overall performance of TENG based on the composite film is greatly enhanced, including an open-circuit voltage of 218 V, a short-circuit current of 14.2 μA, a transferred charge of 60 nC, and a power density of 24.625 μW/cm2. The achieved output voltage, current, and transferred charge are 6.8, 9.7, and 10 times higher than those of TENG comprising of pure PDMS, respectively. The TENG designed also successfully lights up 212 light-emitting diodes and charges the electronic devices without any charging equipment. Besides, it can be used as a favorable motion monitoring device. This work provides a facile and effective approach to enhance the overall performance of TENG by utilizing an elaborately designed flexible negative friction layer. The resulting TENG will have a respectable application prospect in self-powered sensing detection and flexible wearable devices.