Graphene reinforced cement-based triboelectric nanogenerator for efficient energy harvesting in civil infrastructure

This paper investigated a graphene reinforced cement-based triboelectric nanogenerator (TENG) aimed at harvesting mechanical energies in infrastructure, such as pedestrians, vehicles, human-induced vibrations, and natural stimulus like wind and earthquakes. The triboelectric layers of the cement-based TENG consisted of a fully cured graphene modified cement-based plate and a polytetrafluoroethylene (PTFE) film, which were tested under a contact-separation mode. Microstructural analysis indicated that the graphene was well-dispersed in the cementitious matrix, and the graphene-cement composites achieved excellent compressive and flexural strengths of 53.0 and 3.5 MPa, respectively. The electrical characteristics of the graphene-cement composites, specifically their resistivity and impedance, showed that they did not reach the percolation threshold, making them ideal dielectric materials with a dielectric constant of 100 at 1 kHz. The performance of the cement-based triboelectric nanogenerator (TENG) varied depending on the amplitude and frequency of the contact-separation cycle. At a frequency of 10 Hz and under a force of 100 N, the short-circuit current and open-circuit voltage peaked at 3.62 µA and 279.4 V, respectively, achieving a maximum power density of 95 mW/m2 with a 100 MΩ resistor. In practical applications, this TENG charged a 10 μF capacitor to 3.1 V within one minute and to 57.2 V in one hour. Additionally, manual operation of the TENG enabled the lighting of 29 LEDs with one minute of hand pressure. By utilizing triboelectric effects, the results provide the feasibility of self-powering concrete structures and pavements for future smart cities.