Defect engineering treatment of indium tin oxide significantly enhances the thermoelectric properties of cement-based composites for large-scale energy harvesting

Abstract

When this cement-based composite with thermoelectric effect is used in roofs or sidewalks, it can capture heat energy through temperature difference and convert it into electrical energy while achieving cooling effect. We propose for the first time the use of indium tin oxide (ITO) powder with very stable thermoelectric properties, which is incorporated into the cement matrix together with expanded graphite (EG) to impart good thermoelectric properties for large-scale energy harvesting. The addition of ITO makes the conductive network of the cement-based composite more complete and increases the electrical conductivity by 1.43 times. The ITO powder was treated with a defect engineering approach to modulate its oxygen vacancy content and significantly increase the carrier concentration, which further brought about a simultaneous increase in the Seebeck coefficient and electrical conductivity, resulting in a 1.60-fold increase in the figure of merit (ZT) value to 1.49 × 10 −5 at 313 K.