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

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_0.5Sb_1.5Te₃ (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 m² 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 cm² 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%.