High-performance and humidity-resilient cement-based triboelectric nanogenerators (CBTENGs) via surface functionalisation

Cement-based triboelectric nanogenerators (CBTENGs) are promising for enabling sustainable energy harvesting in intelligent civil infrastructure. However, performance degradation in humid and wet environments remains a critical challenge. This study presents a comprehensive strategy that combines functional fillers and surface modification to enhance both the electric output performance and environmental adaptability of CBTENGs. Recycled graphitic carbon materials derived from hydrogen production are incorporated into cement matrices to optimise charge-trapping and dielectric behavior. Two cementitious surface techniques – oxygen plasma treatment and perfluorooctyltriethoxysilane (POTS) coating via chemical vapor deposition – were systematically compared. While oxygen plasma treatment introduces polar functional groups that increase hydrophilicity and suppress output, POTS coatings render the cementitious surface highly hydrophobic, significantly improving charge retention in moist conditions. The optimised CBTENG (containing 0.5 wt% graphitic carbon and a POTS coating) achieves a peak open-circuit voltage of ∼480 V and a short-circuit current of ∼3 µA, and can sustain performance in wet conditions with over 75 % output retention. Several practical applications are demonstrated, including capacitor charging, LED powering, wind-driven energy harvesting from a house roof, and pavement-based energy collection under wet traffic conditions. The results provide an innovative approach to achieving durable and high-performance CBTENGs, advancing the integration of energy-harvesting concrete into smart and self-powering infrastructure systems.