Cement-Based Thermoelectric Device for Protection of Carbon Steel in Alkaline Chloride Solution

Abstract

The thermoelectric cement-based materials can convert heat into electricity; this makes them promising candidates for impressed current cathodic protection of carbon steel. However, attempts to use the thermoelectric cement-based materials for energy conversion usually results in low conversion efficiency, because of the low electrical conductivity and Seebeck coefficient. Herein, we deposited polyaniline on the surface of MnO2 and fabricated a cement-based thermoelectric device with added PANI/MnO2 composite for the protection of carbon steel in alkaline chloride solution. The nanorod structure (70~80 nm in diameter) and evenly dispersed conductive PANI provide the PANI/MnO2 composite with good electrical conductivity (1.9 ± 0.03 S/cm) and Seebeck coefficient (−7.71 × 103 ± 50 μV/K) and, thereby, increase the Seebeck coefficient of cement-based materials to −2.02 × 103 ± 40 μV/K and the electrical conductivity of cement-based materials to 0.015 ± 0.0003 S/cm. Based on this, the corrosion of the carbon steel was delayed after cathodic protection, which was demonstrated by the electrochemical experiment results, such as the increased resistance of the carbon steel surface from 5.16 × 102 Ω·cm2 to 5.14 × 104 Ω·cm2, increased charge transfer resistance from 11.4 kΩ·cm2 to 1.98 × 106 kΩ·cm2, and the decreased corrosion current density from 1.67 μA/cm2 to 0.32 μA/cm2, underlining the role of anti-corrosion of the PANI/MnO2 composite in the cathodic protection system.

Study on the Effect of Freeze–Thaw Action on the Electrical Conductivity and Sensing Properties of Graphene-Based Cement Composites

“…When necessary, it can also be directly used as a structural component to monitor the performance of the entire component without dead angles. So, the cement-based conductive composite is provided with broad application prospects [ 12 , 13 , 14 , 15 , 16 , 17 ]. Graphene [ 18 ] has become a new favorite for the preparation of cement-based conductive composites due to its excellent tensile strength, thermal conductivity and electrical conductivity, which can endow cement-based materials with certain functional properties.…”