Enhanced thermoelectric performance of a new half-Heusler derivative Zr9Ni7Sn8 bulk nanocomposite: enhanced electrical conductivity and low thermal conductivity

Misra, Debasmita; Bhardwaj, A.; Singh, Sanjay

doi:10.1039/c4ta01380h

Cited by 47 publications

(29 citation statements)

References 55 publications

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“…as well as a low value of k. A large value for the power factor of a material requires it to possess a large effective mass (m*) and high carrier mobility m. 2 Several strategies such as doping, [3][4][5][6] solid solution alloying, [7][8][9][10] and nanostructuring/nanocomposite, [11][12][13][14][15][16] have been utilized to modify the structure, hence improving the thermoelectric properties. Such microstructural modications lead to several important mechanisms e.g.…”

Section: Introductionmentioning

confidence: 99%

Graphene boosts thermoelectric performance of a Zintl phase compound

et al. 2015

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The concept of nanocomposites derived by incorporating a second minor phase in bulk thermoelectric materials has established itself as an effective paradigm for optimizing high thermoelectric performance.In this work, this paradigm is for the first time extended to bulk Zintl phase Mg 3 Sb 2 and its isoelectronically Bi-doped derivative Mg 3 Sb 1.8 Bi 0.2 system. Herein, we report the synthesis, microstructural details, electronic structure and thermoelectric properties of (Mg 3 Sb 2 , Mg 3 Sb 1.8 Bi 0.2 )/ graphene nanosheet (GNS) nanocomposites with different mass ratios. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) investigation reveals that Mg 3 Sb 2 nanoparticles are homogenously anchored on the surface of GNS. We demonstrate that Mg 3 Sb 2 -based materials incorporated with a small content of graphene outperform optimally, resulting in potential ptype thermoelectric materials. The present nanocomposite additive of GNS deriving such a novel nanocomposite of (Mg 3 Sb 2 , Mg 3 Sb 1.8 Bi 0.2 )/GNS, enhances the electrical conductivity significantly, thereby resulting in a substantially large increase in the power factor. The enhanced electrical conductivity of these nanocomposites is attributed to the increase in the carrier concentration and high carrier mobility owing to the ultra high mobility of graphene. X-ray photoelectron spectroscopy (XPS) core level spectra confirm weak bonding between GNS and Mg 3 Sb 2 . Increase in carrier concentration is reflected in XPS valence band spectra and change in spectral weight near valence band maxima is indicative of increased electrical conductivity in the nanocomposite material. The thermal conductivity of these nanocomposites is noted to be reduced at high temperature. These favorable conditions lead to enhanced thermoelectric figure-of-merit (ZT) z 0.71 at 773 K for Mg 3 Sb 2 /GNS and a ZT z 1.35 at 773 K for Mg 3 Sb 1.8 Bi 0.2 /GNS nanocomposites with the mass ratio of 80 : 1 which are $170% and $125% higher values compared to bare Mg 3 Sb 2 and bare Mg 3 Sb 1.8 Bi 0.2 respectively. We strongly believe that the present novel strategy of fabricating such a nanocomposite of a Zintl compound by utilizing GNS as a nanocomposite additive, may provide an emerging path for improving thermoelectric properties of various Zintl phase compounds.

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Section: Introductionmentioning

confidence: 99%

Graphene boosts thermoelectric performance of a Zintl phase compound

et al. 2015

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“…However, several reports show that a partial decoupling between these parameters can be achieved by adapting several strategies namely (1) doping mechanism 4-7 (2) nanostructuring/ nanocomposite [8][9][10][11][12] and (3) ideally engineered materials [13][14][15][16][17] with the electronic properties of a crystal and low thermal conductivity of a glass, the so called phonon glass electron crystal (PGEC). Following these concepts, in the last decade, many materials such as Bi 2 Te 3 , 12,[18][19][20][21] AgPb m SbTe 2+m (LAST), 14 TeAgGeSb, 15 PbTe, 16,22 SiGe 17, 23 and Zintl phase compounds 5,7,[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] have been widely investigated for their high ZT.…”

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Enhancing thermoelectric properties of a p-type Mg₃Sb₂- based Zintl phase compound by Pb substitution in the anionic framework

2014

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“…The thermal stability, mechanical strength, and semiconducting behavior of 18 valence electron count (VEC) hH alloys make them promising prospects for TE applications. Despite having a high power factor (PF), S 2 σ, the high thermal conductivity lowers the efficiency of hH alloys [7][8][9][10][11] . In recent years, different approaches have been adopted to enhance the efficiency of hH alloys.…”

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Hole-doped cobalt-based Heusler phases as prospective high-performance high-temperature thermoelectrics

Zeeshan

Brink

Kandpal

2017

Phys. Rev. Materials

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Materials design based on first-principles electronic calculations has proven a fruitful strategy to identify new thermoelectric materials with a favorable figure of merit. Recent electronic structure calculations predict that in cobalt-based half-Heusler systems a power factor higher than in CoTiSb can be achieved upon p-type doping of CoVSn, CoNbSn, CoTaSn, CoMoIn, and CoWIn. Here, using a first-principles approach and semi-classical Boltzmann transport theory, we investigate the electrical and thermal transport properties of these materials. The calculated thermal conductivity at room temperature of all the systems is lower than that of CoTiSb, with CoMoIn and CoWIn having an almost 3-fold lower thermal conductivity than CoTiSb. We also provide conservative estimates of the figure of merit for these systems which all turn out to be higher than in CoTiSb and to have a maximum value for CoWIn.

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Enhanced thermoelectric performance of a new half-Heusler derivative Zr₉Ni₇Sn₈ bulk nanocomposite: enhanced electrical conductivity and low thermal conductivity

Cited by 47 publications

References 55 publications

Graphene boosts thermoelectric performance of a Zintl phase compound

Graphene boosts thermoelectric performance of a Zintl phase compound

Enhancing thermoelectric properties of a p-type Mg₃Sb₂- based Zintl phase compound by Pb substitution in the anionic framework

Hole-doped cobalt-based Heusler phases as prospective high-performance high-temperature thermoelectrics

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Enhanced thermoelectric performance of a new half-Heusler derivative Zr9Ni7Sn8 bulk nanocomposite: enhanced electrical conductivity and low thermal conductivity

Cited by 47 publications

References 55 publications

Graphene boosts thermoelectric performance of a Zintl phase compound

Graphene boosts thermoelectric performance of a Zintl phase compound

Enhancing thermoelectric properties of a p-type Mg3Sb2- based Zintl phase compound by Pb substitution in the anionic framework

Hole-doped cobalt-based Heusler phases as prospective high-performance high-temperature thermoelectrics

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Enhanced thermoelectric performance of a new half-Heusler derivative Zr₉Ni₇Sn₈ bulk nanocomposite: enhanced electrical conductivity and low thermal conductivity

Enhancing thermoelectric properties of a p-type Mg₃Sb₂- based Zintl phase compound by Pb substitution in the anionic framework