Portland Cement-TiO2 triboelectric nanogenerator for robust large-scale mechanical energy harvesting and instantaneous motion sensor applications

The cement-based triboelectric nanogenerator (TENG) was developed for the first time to harvest mechanical energy. With the use of TiO2 nanoparticles as a filler material at 0.2%wt in Portland cement, the cement-TiO2 nanocomposite can generate high electrical output under a vertical contact-separation mode, which was three times higher than the pristine cement TENG. The maximum power density of 265 mW/m(2) can be achieved. In addition, the fabricated TENG can detect a motion force as small as 0.6 N under finger touching. The high performance of the fabricated TENG is due to the enhanced dielectric property of cement-TiO2 nanocomposite. The TiO2 nanoparticles are also found to improve the mechanical strength of cement by increasing compressive strength approximately 1.3 times of that of ordinary Portland cement. Moreover, the cement-TiO2 TENG prepared by mechanical mixing resulted in superior energy conversion efficiency compared to those prepared by ball milling technique. The cement with a small amount of TiO2 nanomaterials with improved energy harvesting performance and mechanical property can be used directly as a base for construction material. Together with the ease of fabrication, the developed cement-based TENGs are thus a good potential for upscaling to a robust large-scale mechanical energy harvesting and a motion sensor application.