Effect of Manganese Dioxide Nanorods on the Thermoelectric Properties of Cement Composites: Fid-Bau Portal

Effect of Manganese Dioxide Nanorods on the Thermoelectric Properties of Cement Composites

Ji, Tao / Zhang, Xiaoying / Zhang, Xiong / Zhang, Yongjuan / Li, Weihua

The Seebeck coefficient of plain cement paste is usually less than $1 μV / ° C$ . To enhance the thermoelectric performance of cement composites, a kind of ${MnO}_{2}$ powder was synthesized and used as a thermoelectric component in this work. The synthesized ${MnO}_{2}$ powder was proven to be a kind of effective thermoelectric component in cement paste. The synthesized ${MnO}_{2}$ powder possesses a nanorod structure with a diameter of about 50 nm and a length up to 1.4 μm. The measured Seebeck coefficient of the compacted ${MnO}_{2}$ powders was about $- 5,490 μV / ° C$ . The nanorod structured design was proven to be an effective method to increase the Seebeck coefficient of the thermoelectric component in this research. Then the ${MnO}_{2}$ nanorods were incorporated into the cement matrix to enhance the thermoelectric effect of cement composites. A relatively high Seebeck coefficient of about $- 3,085 μV / ° C$ could be obtained when the content of ${MnO}_{2}$ powder was 5.0% by weight of cement, which is more than 1,000 times higher than that of the cement paste without ${MnO}_{2}$ powder. And at this content, the electrical conductivity, thermal conductivity, and $Z T$ of cement composites were $1.88 \times 10^{- 4} S / m$ , $0.72 W / mK$ , and $7.596 \times 10^{- 7}$ , respectively. The thermoelectric effect of the cement composites is enhanced mainly due to the enhanced Seebeck coefficient, while the influence of electrical conductivity and thermal conductivity caused by ${MnO}_{2}$ powders is not as obvious as Seebeck coefficient.