High thermoelectric performance of In, Yb, Ce multiple filled CoSb3 based skutterudite compounds

Ballıkaya, Sedat; Üzar, Neslihan; Yıldırım, Sinem; Salvador, James R.; Uher, Ctirad

doi:10.1016/j.jssc.2012.03.029

Cited by 64 publications

(24 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the case of heavily doped semiconductors, the mobility ratio however is no longer a valid guide for understanding or predicting κ b , due to the substantially different majority and minority carrier concentrations. For example, recent experiments showed significant κ b in p -ty p e heavily-doped skutterudites despite of the mobility ratio between two carriers being greater than 10 (hole mobility ~1–5 cm 2 /V-s with a concentration of ~10 21 cm −3 and electron mobility ~30–50 cm 2 /V-s with a concentration of ~10 18 –10 19 cm −3 at 800 K, according to our numerical analyses which are presented below)1415161718, while the n-type skutterudites do not show appreciable κ b , consistent with the rather small b value (~1/50)1920212223242526272829. Similar observations have been reported for many other semiconductors30313233343536373839.…”

supporting

confidence: 84%

Conductivity-limiting bipolar thermal conductivity in semiconductors

Wang

Yang

Toll

et al. 2015

Sci Rep

121

101

View full text Add to dashboard Cite

Intriguing experimental results raised the question about the fundamental mechanisms governing the electron-hole coupling induced bipolar thermal conduction in semiconductors. Our combined theoretical analysis and experimental measurements show that in semiconductors bipolar thermal transport is in general a “conductivity-limiting” phenomenon, and it is thus controlled by the carrier mobility ratio and by the minority carrier partial electrical conductivity for the intrinsic and extrinsic cases, respectively. Our numerical method quantifies the role of electronic band structure and carrier scattering mechanisms. We have successfully demonstrated bipolar thermal conductivity reduction in doped semiconductors via electronic band structure modulation and/or preferential minority carrier scatterings. We expect this study to be beneficial to the current interests in optimizing thermoelectric properties of narrow gap semiconductors.

show abstract

supporting

confidence: 84%

Conductivity-limiting bipolar thermal conductivity in semiconductors

Wang

Yang

Toll

et al. 2015

Sci Rep

121

101

View full text Add to dashboard Cite

show abstract

“…37 To unravel the underlying reason for the anomalies in the electrical transport, the high-temperature (300-700 K) n H and μ H were measured and are shown in Figures 5c and d 40 which show weakly temperature-dependent n H , the n H of Yb x Co 4 Sb 12 increases significantly with increasing temperature, which has been widely observed for filled skutterudites. 9,29,[41][42][43] The rapid rise in n H starting at very low temperatures 41 should be irrelevant to the intrinsic conduction or temperature-dependent solubility of fillers. We speculate that this phenomenon should relate to the unusual temperature dependence of valence state of fillers, which most likely gradually increase their valence states with increasing temperature; this behavior is attributable to the gradual ionization of Yb.…”

Section: Te Transport Propertiesmentioning

confidence: 99%

High-performance n-type YbxCo4Sb12: from partially filled skutterudites towards composite thermoelectrics

et al. 2016

View full text Add to dashboard Cite

The filling fraction limit (FFL) of skutterudites, that is, the complex balance of formation enthalpies among different species, is an intricate but crucial parameter for achieving high thermoelectric performance. In this work, we synthesized a series of Yb x Co 4 Sb 12 samples with x = 0.2-0.6 and systemically studied the FFL of Yb, which is still debated even though this system has been extensively investigated for decades. Our combined experimental efforts of X-ray diffraction, microstructural and quantitative compositional analyses clearly reveal a Yb FFL of~0.29 in CoSb 3 , which is consistent with previous theoretical calculations. The excess Yb in samples with x40.35 mainly form metallic YbSb 2 precipitates, significantly raising the Fermi level and thus increasing the electrical conductivity and decreasing the Seebeck coefficient. This result is further corroborated by the numerical calculations based on the Bergman's composite theory, which accurately reproduces the transport properties of the x40.35 samples based on nominal Yb 0.35 Co 4 Sb 12 and YbSb 2 composites. A maximum ZT of 1.5 at 850 K is achieved for Yb 0.3 Co 4 Sb 12 , which is the highest value for a single-element-filled CoSb 3 . The high ZT originates from the high-power factor (in excess of 50 μW cm-K − 2 ) and low lattice thermal conductivity (well below 1.0 W m-K − 1 ). More importantly, the large average ZTs, for example,~1.05 for 300-850 K and~1.27 for 500-850 K, are comparable to the best values for n-type skutterudites. The high thermoelectric and thermomechanical performances and the relatively low air and moisture sensitivities of Yb make Yb-filled CoSb 3 , a promising candidate for large-scale power generation applications.

show abstract

“…A series of In-filled skutterudites of various groups prepared with various methods followed and confirmed that indium was useful as a filler. These investigations were extended to double-filled skutterudites of In with Sn [29], with Ba [3,16,[30][31][32][33][34][35][36][37], with Tl [38], with Pb [35], with Ce [6,[39][40][41][42], with Pr [27], with Nd [21,43], with Yb [7,8,16,19,[44][45][46][47][48][49], with Lu [50], and to triple filled skutterudites of In with Ba and Ce [51], with Ba and Yb [16,52], with La and Yb [47], with Ce and Yb [41,42,53] and Ga and Tl [26]. There are also attempts to improve the TE properties by doping and/or alloying e.g.…”

Section: Introductionmentioning

confidence: 99%