Thermoelectric Properties of Multifilled Skutteruditeswith La as the Main Filler

Bulk multifilled n- and p-type skutterudites with La as the main filler were fabricated using the spark plasma sintering (SPS) method. The thermoelectric properties and thermal stability of these skutterudites were investigated. It was found that the interactions among the filling atoms also play a vital role in reducing the lattice thermal conductivity of the multifilled skutterudites. ZT = 0.76 for p-type La_0.8Ba_0.01Ga_0.1Ti_0.1Fe₃CoSb₁₂ and ZT = 1.0 for n-type La_0.3Ca_0.1Al_0.1Ga_0.1In_0.2Co_3.75Fe_0.25Sb₁₂ skutterudites have been achieved. Furthermore, the differential scanning calorimetry (DSC) results show that there is no skutterudite phase decomposition till 750°C for the La_0.8Ba_0.01Ga_0.1Ti_0.1Fe₃CoSb₁₂ sample. The thermal stability of the La_0.8Ba_0.01Ga_0.1Ti_0.1Fe₃CoSb₁₂ skutterudite is greatly improved. Using the developed multifilled skutterudites, the fabricated module with size of 50 mm × 50 mm × 7.6 mm possesses maximum output power of 32 W under the condition of hot/cold sides = 600°C/50°C.