Abstract
Composites were prepared,through hot pressing,using carbon materials with different pore size distribu-tions as additives for commercial Bi0.5Sb1.5Tes thermoelectric material (BST,p-type).Thermoelectric prop-erties of the composites were measured in a temperature range of 298-473 K.Thermal conductivity of the composites,especially lattice thermal conductivity,was effectively decreased due to the mesoporous properties of the incorporated carbon additives.The electrical conductivity of the composites slightly de-creased due to the electron scattering at the interface between the carbon material and the commercial BST matrix.The composite with 0.2 vol.％ mesoporous carbon powder (36％ mesoporosity) exhibited a figure of merit value approximately 10.7％ higher than that of commercial BST without additives.This be-havior resulted in 116％ improved output power in the composite block-based single element compared with a bare BST thermoelectric block.The enhanced figure of merit was attributed to the effective re-duction of lattice thermal conductivity by acoustic phonons scattering at the interface between the BST matrix and the mesoporous carbon as well as at the pore surfaces within the mesoporous carbon.By utilizing mesoporous carbon materials used in this study,the shortcomings and economic difficulties of the composite process with low dimensional carbon additives (carbon nanotubes,graphene,and nanodi-amond) can be overcome for extensive practical applications.Mesoporous carbon powder with a tailored porosity distribution revealed the validity of bulk-type carbon additives to enhance the figure of merit of commercial thermoelectric materials.
基金项目
National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT)(NRF-2018R1A4A1022260)
NETL
NSTL
万方数据