Thermoelectric Properties of Ca3Co2−xMnxO6 (x = 0.05, 0.2, 0.5, 0.75, and 1)
AbstractHigh-temperature instability of the Ca3Co4−yO9+δ and CaMnO3−δ direct p-n junction causing the formation of Ca3Co2−xMnxO6 has motivated the investigation of the thermoelectric performance of this intermediate phase. Here, the thermoelectric properties comprising Seebeck coefficient, electrical conductivity, and thermal conductivity of Ca3Co2−xMnxO6 with x = 0.05, 0.2, 0.5, 0.75, and 1 are reported. Powders of the materials were synthesized by the solid-state method, followed by conventional sintering. The material Ca3CoMnO6 (x = 1) demonstrated a large positive Seebeck coefficient of 668 μV/K at 900 °C, but very low electrical conductivity. Materials with compositions with x < 1 had lower Seebeck coefficients and higher electrical conductivity, consistent with small polaron hopping with an activation energy for mobility of 44 ± 6 kJ/mol and where both the concentration and mobility of hole charge carriers were proportional to 1−x. The conductivity reached about 11 S·cm−1 at 900 °C for x = 0.05. The material Ca3Co1.8Mn0.2O6 (x = 0.2) yielded a maximum zT of 0.021 at 900 °C. While this value in itself is not high, the thermodynamic stability and self-assembly of Ca3Co2−xMnxO6 layers between Ca3Co4−yO9+δ and CaMnO3−δ open for new geometries and designs of oxide-based thermoelectric generators. View Full-Text
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Kanas, N.; Singh, S.P.; Rotan, M.; Desissa, T.D.; Grande, T.; Wiik, K.; Norby, T.; Einarsrud, M.-A. Thermoelectric Properties of Ca3Co2−xMnxO6 (x = 0.05, 0.2, 0.5, 0.75, and 1). Materials 2019, 12, 497.
Kanas N, Singh SP, Rotan M, Desissa TD, Grande T, Wiik K, Norby T, Einarsrud M-A. Thermoelectric Properties of Ca3Co2−xMnxO6 (x = 0.05, 0.2, 0.5, 0.75, and 1). Materials. 2019; 12(3):497.Chicago/Turabian Style
Kanas, Nikola; Singh, Sathya P.; Rotan, Magnus; Desissa, Temesgen D.; Grande, Tor; Wiik, Kjell; Norby, Truls; Einarsrud, Mari-Ann. 2019. "Thermoelectric Properties of Ca3Co2−xMnxO6 (x = 0.05, 0.2, 0.5, 0.75, and 1)." Materials 12, no. 3: 497.
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