PEDOT: PSS‐Enabled CNT and Bi _0.5 Sb _1.5 Te ₃ Interface Microengineering for Integrated Thermoelectric Energy Harvesting and Corrosion Protection in Cementitious Composite

Abstract Thermoelectric cement‐based composites integrate thermoelectric effects with structural capabilities, presenting an effective solution for harvesting environmental heat in self‐powered cathodic protection. While the prospects are promising, their performance has been constrained by the compatibility between functional fillers and cementitious materials. This study demonstrates that PEDOT: PSS(PP) significantly improves the dispersion of multi‐walled carbon nanotube (CNT) and Bi _0.5 Sb _1.5 Te ₃ (BST) in cementitious materials. The optimized composite(0.2 wt.% CNT, 1.0 vol% PP, and 1.0 wt.% BST) exhibits a 28.4% increase in conductivity and a 15.9% reduction in thermal conductivity compared to the control. Additionally, it achieves an impressive Seebeck coefficient of 450 µV K ⁻¹ . Importantly, the composite maintains superior compressive strength (> 40 MPa) and chloride penetration resistance (< 7 × 10 ⁻¹² m ² s ⁻¹ ), with over 80% property retention after 60 days under extreme temperatures of −20 or 70 °C. A thermoelectric generator (TEG) is assembled by connecting 30 specimens in series to form a 10 × 10 cm ² device. The TEG exhibits less than 8% voltage decay during 20 h of continuous operation and successfully powered an LED. The TEG also substantially mitigates steel corrosion in self‐powered cathodic protection, reducing corrosion current density and corrosion rate by more than 47%.