Enhanced thermoelectric and compressive performance of MnO2 coated carbon fiber/cement composites by microwave electrodeposition/microwave alkali treatment

Abstract

The microwave electrodeposition/microwave NaOH aqueous solution treatment was developed for the first time to prepare MnO2 modified carbon fiber/cement composite (MCFC). The effects of the MnO2 modified carbon fiber (MCF) content and alkali treatment temperatures on the thermoelectric properties of the cement composites were investigated. The results show that the composite with the MCF content of 3.75 wt% has the optimal thermoelectric performance. After microwave alkali treatment at 333K, this composite has a Seebeck coefficient of −2308.9 μV/K, electrical and thermal conductivities of 2.72 S/m and 0.632 W/mK, and as a result, the ZT value of 7.73 × 10−3 could be achieved, which is the best value among the reported carbon fiber cement composites. Moreover, the composite has a compressive strength and strain of 38.6 MPa and 2.8%, respectively, which are 15.2% and 75% higher than those of the original cement, and shows good toughness.