Work

Anomalous lattice thermal conductivity in SrLi X ( X = P, As) Zintl phases via anion engineering

Year: 2026

Type: article

Abstract: Thermoelectric materials show promise for converting waste heat into electricity, addressing energy sustainability challenges. The ZrBeSi-type Zintl phase compounds, featuring a layered structure, intrinsically exhibit low lattice thermal conductivity ( κ L ). Motivated by this feature, we employed first-principles calculations combined with Boltzmann transport theory to systematically investigate the thermoelectric transport properties of SrLi X ( X = P, As). SrLiP exhibits a κ L of 0.98 W⋅m −1 ⋅K −1 at 900 K, which is 34% lower than that of SrLiAs (1.48 W⋅m −1 ⋅K −1 ), despite its smaller average atomic mass. This anomalous reduction originates from the broader phonon bandwidth in SrLiP, which is a direct consequence of anion regulation, and this broader bandwidth substantially expands the three-phonon scattering phase space and enhances phonon scattering rates. Meanwhile, n -type SrLiAs and SrLiP reach power factors of 1.14 mW⋅m −1 ⋅K −2 and 1.33 mW⋅m −1 ⋅K −2 at 900 K, respectively, benefiting from multiple band convergence near the Fermi level that yields a valley degeneracy. Ultimately, our calculations yield ZT values of 0.73 for n -type SrLiP and 0.48 for n -type SrLiAs at 900 K. Our results demonstrate that anion engineering successfully decouples thermal and electrical transport, simultaneously suppressing lattice thermal conductivity while maintaining favorable electrical transport properties. This offers a viable strategy for designing high-performance thermoelectrics.

Source: Chinese Physics B

DOI: 10.1088/1674-1056/ae9075