Abstract
The Te-/Se-doped n-type Co4Sb11.3Te0.5Se0.2 skutterudite thermoelectric bulk was successfully fabricated by the combination of microwave synthesis and spark plasma sintering technique. The microstructure and the electrical and thermal transport properties have been systematically investigated. The experimental results show that nearly single-phase skutterudites grow in merely 5 min microwave heating. The average matrix grain size of Co4Sb11.3Te0.5Se0.2 is ∼2 μm. The carrier concentration and mobility of Co4Sb11.3Te0.5Se0.2 are 1.943×1020 n/cm-3 and 23.17 cm2V-1s-1, respectively. The maximum Seebeck coefficient is -204 μVK-1. The lattice and total thermal conductivity from room temperature to 773K are 2.11∼3.32 and 2.88∼3.78 Wm-1K-1, respectively. The highest ZT of 0.59 of Co4Sb11.3Te0.5Se0.2 was achieved at 673 K. The present synthetic method is superior especially in term of the synthesis efficiency.
Highlights
INTRODUCTIONThe TE properties of a material can be evaluated by a dimensionless figure of merit, ZT, defined as ZT = S2σT/κ, where S, σ, κ and T are the Seebeck coefficient, electrical conductivity, thermal conductivity and absolute temperature, respectively
Thermoelectric (TE) materials can convert heat to electricity or electricity to heat based on the Seebeck or Peltier effects.1 The TE properties of a material can be evaluated by a dimensionless figure of merit, ZT, defined as ZT = S2σT/κ, where S, σ, κ and T are the Seebeck coefficient, electrical conductivity, thermal conductivity and absolute temperature, respectively
For unfilled CoSb3, it has been found that Te substitution is effective in improving the electrical transport scitation.org/journal/adv properties through affecting the carrier concentration,11–13 whereas substituting Se for Sb is effective in reducing the thermal conductivity because of the chemical disorder associated with mass and volume fluctuations
Summary
The TE properties of a material can be evaluated by a dimensionless figure of merit, ZT, defined as ZT = S2σT/κ, where S, σ, κ and T are the Seebeck coefficient, electrical conductivity, thermal conductivity and absolute temperature, respectively. In the family of skutterudite compounds, CoSb3-based material attracts the most intensive interest to researchers due to their good electronic properties and mechanical properties. The inherent high thermal conductivity would result in a low dimensionless thermoelectric figure of merit ZT.. The TE properties of CoSb3-based skutterudite can be improved via filling or doping process.. Properties through affecting the carrier concentration, whereas substituting Se for Sb is effective in reducing the thermal conductivity because of the chemical disorder associated with mass and volume fluctuations.. Se-/Te-doped bulk skutterudite Co4Sb11.3Te0.5Se0.2 was fabricated by the combination of microwave synthesis and spark plasma sintering (SPS). The electrical resistivity, Seebeck coefficient and thermal conductivity were systematically investigated in the temperatures range from 300 K to 773 K
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