Optimizing Thermoelectric Efficiency in Cementitious Nanocomposites via Hybrid SWCNT/NCF Reinforcement

Cement-based materials with thermoelectric functionalities offer new opportunities for harvesting waste heat from civil infrastructure. While carbon nanomaterials have been shown to enhance the electrical conductivity of cementitious composites, achieving efficient thermoelectric energy conversion requires simultaneously controlling the thermal properties while preserving the electrical properties. In this study, insulating cellulose nanofibrils (NCFs) are combined with superconducting single-walled carbon nanotubes (SWCNTs) to develop nano-engineered cementitious materials capable of converting thermal gradients into electrical energy. Results show that the hybrid SWCNT/NCF mortars exhibited a Seebeck coefficient up to 4083.61 μV/K and ZT of 0.46 while maintaining high electrical conductivity of 126.42 S/m and a reduced thermal conductivity of 0.84 W/m·K.