Defect-Controlled Electronic Structure and Phase Stability in Thermoelectric Skutterudite CoSb<sub>3</sub>

Li, Guodong; Aydemir, Umut; Wood, Max; Goddard, William A.; Zhai, Pengcheng; Zhang, Qingjie; Snyder, G. Jeffrey

doi:10.1021/acs.chemmater.7b00559

Cited by 22 publications

(15 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This leads to a much weaker Mg−Si bond in the TBs than that in the Mg 2 Si crystal. The upper half of the nanotwinned Mg 2 Si is the (1-1-1) [1][2][3][4][5][6][7][8][9][10][11][12] slip system, while the lower half is (1-1-1)[-11-2]. Our previous DFT simulations suggested that the (1-1-1)[- slip system is the most likely under pressure [49].…”

Section: Resultsmentioning

confidence: 99%

“…The current strategies for enhancing the zT value are mainly focused either on improving the power factor (S 2 σ) by tailoring the electrical transport properties [6,7] or on reducing κ L through phonon scattering [8][9][10][11]. Due to the strong correlation between S, σ, and κ E , traditional strategy of carrier optimization is often not very effective in improving zT [1,12,13].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Dramatically reduced lattice thermal conductivity of Mg2Si thermoelectric material from nanotwinning

et al. 2019

Acta Materialia

Self Cite

View full text Add to dashboard Cite

Dramatically reduced lattice thermal conductivity of Mg 2 Si thermoelectric material from nanotwinning, Acta Materialia, https://doi. Abstract:Tuning phonon transport to reduce the lattice thermal conductivity (κ L ) is crucial for advancing thermoelectrics (TEs). Traditional strategies on κ L reduction focus on introducing scattering sources such as point defects, dislocations, and grain boundaries, that may degrade the electrical conductivity and Seebeck coefficient. We suggest here, a novel twin boundary (TB) strategy that can decrease the κ L of Mg 2 Si by ~90%, but which may not degrade the electrical properties significantly. We validate this suggestion using density functional theory (DFT). We attribute the mechanism of TB induced κ L reduction to (i) the lower phonon velocities and larger Grüneisen parameter, (ii) "rattling" of the Mg−Mg pair induced soft acoustic and optical modes, (iii) shorter phonon lifetime and higher phonon scattering rate. We predict that the size of nanotwinned structure should be controlled between 3 nm and 100 nm in the Mg 2 Si matrix for the most effective κ L reduction. These results should be applicable for other TE or non TE energy materials with desired low thermal conductivity, suggesting rational designs of high-performance Mg 2 Si TE materials with low κ L for the energy conversion applications. Functional Theory 0.4 W m −1 K −1 and a zT of 1.5 at 1000 K [21]. In SnSe single crystals, The lattice anharmonicity leads to an exceptionally low κ L of 0.23 ± 0.03 W m −1 K −1 and an unprecedented zT of 2.6 ± 0.03 at 923 K [22,23]. In such TE materials as MgAgSb [24], Ag 5-δ Te 3 [25], and Ag 8 SnSe 6 [26], the complex crystal structure or weak chemical bonds leads to low heat capacity or low speed of sound, well explaining the low intrinsic κ L of < 0.5 W m −1 K [24-26]. Introducing phonon scattering sources such as point defects [27-29], dislocations [30-32], grain boundaries [33-35], can effectively shorten phonon relaxation time, giving rise to reduction in κ L . Multiple fillers inCoSb 3 can achieve broad-frequency phonon scattering, reducing κ L to the glass limit value of 0.2 W m −1 K −1 , and leading to an extremely high zT of 1.7 at 850 K [29]. Full-spectrum phonon scattering, which was achieved through grain boundary, dense dislocation arrays, and point defect,

show abstract

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Dramatically reduced lattice thermal conductivity of Mg2Si thermoelectric material from nanotwinning

et al. 2019

Acta Materialia

Self Cite

View full text Add to dashboard Cite

show abstract

“…Relevant reports have investigated an electron count model based on the stability of a wide number of skutterudites, [ 38 ] and the local distortions upon filling and doping, described by a charge compensated compound defect model. [ 39 ] Besides, thermoelectric properties of skutterudites have been investigated by the defect formation effect on [Sb 4 ] rings by electronegative dopants, [ 40 ] the discontinuity of structural parameters at the n/p crossover on increasing filler and Fe content, [ 41 ] the relation of the structural changes with band convergence, [ 42,43 ] and new emergent states [ 44 ] at the conduction band minima. These studies focus on the n‐type behavior by increasing the chemical potential using one type of filler element, while the scope of wider reviews does not include the structural features of filling.…”

Section: Introductionmentioning

confidence: 99%

Unveiling the Correlation between the Crystalline Structure of M‐Filled CoSb₃ (M = Y, K, Sr) Skutterudites and Their Thermoelectric Transport Properties

Gainza

Serrano‐Sánchez

Rodrigues

et al. 2020

Adv Funct Materials

View full text Add to dashboard Cite

Skutterudite‐type pnictides based on CoSb3 are promising semiconductor materials for thermoelectric applications. An exhaustive structural characterization by synchrotron X‐ray powder diffraction of different M‐filled CoSb3 (M = Y, K, Sr, La, Ce, Yb) skutterudites, with a panoply of M atoms with very different chemical nature, allows to better understand the effects of filling from a crystallo‐chemical point of view. These analyses focus on the correlation of chemical and structural features with the enhanced thermoelectric properties displayed by certain families of filled‐CoSb3 skutterudites. These are mainly determined by Sb positional parameters, yielding Oftedal plots that depend on the filling fraction, ionic state, and atomic radius of the filler. Together with the distortion of [Sb4] rings and [CoSb6] octahedra present in the skutterudite structure, these results are linked to the band‐convergence concept and its influence on the thermoelectric transport properties. Here, the structural changes observed in the different chemical compositions are relevant to understand the improved thermoelectric performance of single partially filled n‐type skutterudites.

show abstract

“…Predictions of carrier concentrations based on the dilute doping assumption are in excellent agreement with experiments, as shown in this work for native BiCuSeO (Section 3.1) and in other studies on Mg 3 Sb 2 , 66 PbTe, 45 KGaSb 4 , 46 and CoSb 3 . 78 In Ref. 11, it is shown that 15 at.…”

Section: P-type Dopantsmentioning

confidence: 99%

Defect Chemistry and Doping of BiCuSeO

Toriyama

Qu²,

Snyder

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

While p-type BiCuSeO is a well-known mid-temperature oxide thermoelectric (TE) material, computations predict that superior TE performance can be realized through n-type doping. In this study, we use firstprinciples defect calculations to show that Cu vacancies are responsible for the native p-type self doping; yet, we find that BiCuSeO is n-type dopable under Cu-rich growth conditions, where the formation of Cu vacancies is suppressed. We computationally survey a broad suite of 23 dopants and find that only Cl and Br are effective n-type dopants. Therefore, we recommend that future experimental doping efforts utilize phase boundary mapping to optimize the electron concentration and resolve the anomalous pn-p transitions observed in halogen-doped BiCuSeO. The prospects of n-type doping, as revealed by our defect calculations, paves the path for rational design of BiCuSeO chemical analogues with similar doping behavior and even better TE performance.

show abstract

Defect-Controlled Electronic Structure and Phase Stability in Thermoelectric Skutterudite CoSb₃

Abstract: Abstract:Controlling extrinsic defects to tune the carrier concentration of electrons or holes is a crucial point concerning the engineering application of thermoelectric semiconductors. To understand the defect-controlled electronic structure in thermoelectric materials, we apply density

Cited by 22 publications

References 48 publications

Dramatically reduced lattice thermal conductivity of Mg2Si thermoelectric material from nanotwinning

Dramatically reduced lattice thermal conductivity of Mg2Si thermoelectric material from nanotwinning

Unveiling the Correlation between the Crystalline Structure of M‐Filled CoSb₃ (M = Y, K, Sr) Skutterudites and Their Thermoelectric Transport Properties

Defect Chemistry and Doping of BiCuSeO

Contact Info

Product

Resources

About

Defect-Controlled Electronic Structure and Phase Stability in Thermoelectric Skutterudite CoSb3

Abstract: Abstract:Controlling extrinsic defects to tune the carrier concentration of electrons or holes is a crucial point concerning the engineering application of thermoelectric semiconductors. To understand the defect-controlled electronic structure in thermoelectric materials, we apply density

Cited by 22 publications

References 48 publications

Dramatically reduced lattice thermal conductivity of Mg2Si thermoelectric material from nanotwinning

Dramatically reduced lattice thermal conductivity of Mg2Si thermoelectric material from nanotwinning

Unveiling the Correlation between the Crystalline Structure of M‐Filled CoSb3 (M = Y, K, Sr) Skutterudites and Their Thermoelectric Transport Properties

Defect Chemistry and Doping of BiCuSeO

Contact Info

Product

Resources

About

Defect-Controlled Electronic Structure and Phase Stability in Thermoelectric Skutterudite CoSb₃

Unveiling the Correlation between the Crystalline Structure of M‐Filled CoSb₃ (M = Y, K, Sr) Skutterudites and Their Thermoelectric Transport Properties