Thermoelectric Performance in Cement-Based Composites

Cement-based composites have emerged as promising multifunctional materials capable of converting waste heat into electrical energy through the thermoelectric effect. By doping conventional cement matrices with conductive fillers such as carbon fibres, carbon nanotubes, graphene nanoplatelets or metal oxides, researchers have engineered percolating networks that simultaneously preserve structural integrity and enable charge transport. The key parameters that govern performance include the Seebeck coefficient, electrical conductivity and thermal conductivity, which together determine the power factor and the dimensionless figure of merit (ZT). In some systems, an ionic thermoelectric contribution arises from mobile ions in the pore solution, augmenting the electronic component and enabling novel p-type and n-type behaviours. Optimisation of microstructure—through control of porosity, hydration chemistry and filler dispersion—has been shown to enhance the voltage output under realistic temperature gradients. These materials hold considerable potential for integration into building envelopes, pavements and protective coatings, transforming passive concrete structures into active energy-harvesting devices. Despite significant advances, challenges remain in scaling up fabrication, ensuring long-term durability under environmental exposure and achieving competitive conversion efficiencies in low-grade heat scenarios.

Research from Nature Portfolio

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Research from all publishers

Recent studies have focused on ultra-lightweight engineered cementitious composites incorporating carbon fibre to achieve low thermal conductivity (0.48–0.67 W·m⁻¹·K⁻¹) and densities near 1100 kg·m⁻³. By varying carbon fibre length and dosage, researchers realised an ionic-electronic thermoelectric effect with Seebeck coefficients up to 5.9 mV °C⁻¹. Saturation and drying treatments were found to modulate the ionic contribution, offering a route to tailor conversion efficiency in building facades.

A parallel investigation explored the influence of water-to-cement ratio and carbon nanotube (CNT) content on both p-type and n-type thermoelectric composites. At a w/c of 0.3 with 0.3 vol% CNT, the Seebeck coefficient reached 743 µV K⁻¹ (p-type) and –428 µV K⁻¹ (n-type), while compressive strength increased by over 60%. The addition of CNTs also accelerated cement hydration, demonstrating that careful tuning of mix design can optimise both mechanical and energy-conversion performance.

Complementary work assessed graphene nanoplatelets combined with metal oxides (Fe₂O₃, ZnO, MnO₂) in cement matrices to fabricate structural thermoelectric generators. Experimental measurements of electrical conductivity, Seebeck coefficient and thermal conductivity were used to predict a power output of up to 1.5 W m⁻² under a 50 °C gradient. A modular design of multilayered cement-based elements was proposed to aggregate voltage and power, highlighting the feasibility of on-site assembly for façade-integrated energy harvesting.

Thermoelectric Performance in Cement-Based Composites publication trend

The graph below shows the total number of articles in thermoelectric performance in cement-based composites across all publications each year (not limited to Nature Index journals).

Technical terms

Seebeck coefficient: A measure of the voltage generated per unit temperature difference across a material, expressed in µV K⁻¹.

Electrical conductivity: The ability of a material to carry electric charge, expressed in S m⁻¹.

Thermal conductivity: A measure of how readily heat flows through a material, expressed in W m⁻¹ K⁻¹.

Figure of merit (ZT): A dimensionless quantity (ZT = S²σT/κ) combining Seebeck coefficient (S), electrical conductivity (σ), temperature (T) and thermal conductivity (κ) to evaluate thermoelectric efficiency.

Ionic thermoelectric effect: Electrical potential generated by the transport of mobile ions (e.g. OH⁻, metal cations) in a temperature gradient, often contributing alongside electronic conduction in cementitious systems.

References

1. Thermoelectric engineered cementitious composites with low thermal conductivity for efficiency improvement of buildings. Energy and Buildings (2024).
2. Thermoelectric cement-based composites containing carbon nanotubes (CNTs): Effects of water-to-cement ratio and CNT dosage. Case Studies in Construction Materials (2024).
3. Estimation of Energy Harvesting by Thermoelectric Cement Composites with Nanostructured Graphene and Metallic Oxides. Journal of Composites Science (2023).