LAUSR

Abstract Ta2O5 nanoparticles were synthesized by thermal decomposition of tantalum (V) ethoxide, and Ca3Co4O9/Ta2O5 composites were fabricated by ball milling. The volume percentage of Ta2O5 nanoparticles in the composites was controlled as 0, 2%, 4%, and 6% in four samples. The existence and dispersion of Ta2O5 nanoparticles in the composites were confirmed by electron microscopies. The Ca3Co4O9/Ta2O5 composite particles were hot-pressed into pellets and sintered for thermoelectric property measurement. The impacts of the Ta2O5 volume percentage on the lattice/electronic thermal conductivity, Seebeck coefficient, electrical conductivity, and thermoelectric Figure of Merit (ZT) of the Ca3Co4O9/Ta2O5 composites were investigated. The results indicated that an increased Ta2O5 volume percentage resulted in decreased electrical conductivity and thermal conductivity. When the Ta2O5 was 4 vol %, the highest Seebeck coefficient, and maximum ZT were observed in the Ca3Co4O9/Ta2O5 composite.