Open Access Research Article Issue
Planar Zintl-phase high-temperature thermoelectric materials XCuSb (X = Ca, Sr, Ba) with low lattice thermal conductivity
Journal of Advanced Ceramics 2022, 11 (10): 1604-1612
Published: 15 September 2022
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A recent discovery of high-performance Mg3Sb2 has ignited tremendous research activities in searching for novel Zintl-phase compounds as promising thermoelectric materials. Herein, a series of planar Zintl-phase XCuSb (X = Ca, Sr, Ba) thermoelectric materials are developed by vacuum induction melting. All these compounds exhibit high carrier mobilities and intrinsic low lattice thermal conductivities (below 1 W·m−1·K−1 at 1010 K), resulting in peak p-type zT values of 0.14, 0.30, and 0.48 for CaCuSb, SrCuSb, and BaCuSb, respectively. By using BaCuSb as a prototypical example, the origins of low lattice thermal conductivity are attributed to the strong interlayer vibrational anharmonicity of Cu–Sb honeycomb sublattice. Moreover, the first-principles calculations reveal that n-type BaCuSb can achieve superior thermoelectric performance with the peak zT beyond 1.1 because of larger conducting band degeneracy. This work sheds light on the high-temperature thermoelectric potential of planar Zintl compounds, thereby stimulating intense interest in the investigation of this unexplored material family for higher zT values.

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