Thermoelectric properties of Sm_xCo₄Sb₁₂ prepared by high pressure and high temperature

Sm_xCo₄Sb₁₂ skutterudite compounds with different Sm addition contents (x = 0.1, 0.2. 0.6, 0.8, 1.0) have been synthesized via the route of high pressure and high temperature (HPHT). In addition, the effect of Sm filling on the thermoelectric properties of Sm_xCo₄Sb₁₂ compounds has been investigated in this paper. All Sm_xCo₄Sb₁₂ compounds exhibit n-type conduction. The temperature dependences of electrical resistivity, Seebeck coefficient have been measured on these compounds in the range of 300-711 K. The experimental results indicate that the Sm doping can help improve their power factors. Among all the samples, Sm_0.1Co₄Sb₁₂ shows the highest power factor of 23.7 μW cm^-1 K^-2 at 568 K. The thermal conductivity of Sm_xCo₄Sb₁₂ measurements had been performed in the temperature range of 300-711 K. The thermal conductivity of Sm_xCo₄Sb₁₂ is significantly low compared to pure CoSb₃. The dimensionless thermoelectric figure of merit ZT increased with increasing temperature in the range of 300-711 K and reached a maximum value of 0.55 for Sm_0.1Co₄Sb₁₂ at 711 K.