Enhanced Thermoelectric Performance of SmBaCuFeO_5+δ/Ag Composite Ceramics

Abstract

Polycrystalline SmBaCuFeO 5+d /Ag composite ceramics have been synthesized by a traditional ceramic processing method. Phase composition and microstructural analyses indicate that with the introduction of Ag additives, the second phases of copper oxides and Ag appear in these composite ceramic samples. The hole concentration and molibility can be enhanced greatly by the addition of Ag particles, which results in a large increase in the electrical conductivity. The thermal conductivity behaviors show that phonons can be scattered effectively by point defects and mesoscale grain boundaries, which remain a slight change in thermal conductivity. A maximum ZT value 0.047 has been achieved at 1023 K in the SmBaCuFeO 5+d / 20 vol% Ag composite ceramic, and is about 16 times than the pure SmBaCuFeO 5+d sample. Our results reveal that Ag addition is an effective way to enhance the thermoelectric properties.

Grain Boundary Phase Segregation for Dramatic Improvement of the Thermoelectric Performance of Oxide Ceramics

“…The observed phenomenon of increased electrical conductivity of n-type CaMnO 3−δ caused by the existence of sparsely distributed p-type CuO at the grain boundaries is also similar to what has been reported for the p-type materials. There is increased electrical conductivity of various p-type ceramics of Ca 3 Co 4 O 9 , SmBaCuFeO x , and Na x Co 2 O 4 caused by the addition of n-type Ag particles. Furthermore, what has been achieved by Ag addition has also been obtained through the addition of alkaline earth elements into different thermoelectric materials. − …”

Development and Applications of Thermoelectric Oxide Ceramics and Devices

“…In the Sr 0.9 La 0.1 TiO 3 +20% Ag composite system shown in Figure 12a-d, the conductive network illustrated in Figure 12d significantly increased σ to ~101.4 S cm −1 and the |S| slightly improved to ~241 µV K −1 at 883 K [25] simultaneously. The (Ca 0.9 Ag 0.1 ) 3 Co 4 O 9 /nano-sized Ag composites [159] were fabricated by a two-step processing method of SPS combined with a heat-treatment and achieved the maximum PF = 0.43 mW/(m•K 2 ), S = 196.90 µV/K, the corresponding κ l = 1.86 W/(m•K), and ZT = 0.24 at 1223 K. In the polycrystalline SmBaCuFeO 5+δ /Ag composite ceramics [160], the hole concentration and mobility can be increased through the conductive effect of the second phases of copper oxides and Ag; thus, the obtained ZT value is about 16 times that of the pure SmBaCuFeO 5+δ sample.…”

The effect of orbital-lattice coupling on the electrical resistivity of YBaCuFeO5 investigated by X-ray absorption

“…2 in 1988 just a year after the discovery of the well-known high-temperature superconductivity of YBa 2 Cu 3 O 7-δ (YBCO) 4 . YBaCuFeO 5+δ is a p -type semiconductor 14 , although its crystal structure is close to that of YBCO and has been mistakenly identified as a high-temperature superconductor 16,17 . Furthermore, the magnetic ordering in YBaCuFeO 5 (YBCFO) is antiferromagnetic (AFM) with a Néel temperature (T N ) of approximately 440 K 6 .…”