High Entropy Semiconductor AgMnGeSbTe₄ with Desirable Thermoelectric Performance

Abstract

A new p-type high entropy semiconductor AgMnGeSbTe 4 with a band gap of ≈0.28 eV is reported as a promising thermoelectric material. AgMnGeSbTe 4 crystallizes in the rock-salt NaCl structure with cations Ag, Mn, Ge, and Sb randomly disordered over the Na site. Thus, a strong lattice distortion forms from the large difference in the atomic radii of Ag, Mn, Ge, and Sb, resulting in a low lattice thermal conductivity of 0.54 W m −1 K −1 at 600 K. In addition, the AgMnGeSbTe 4 exhibits a degenerate semiconductor behavior and a large average power factor of 10.36 µW cm −1 K −2 in the temperature range of 400-773 K. As a consequence, the AgMnGeSbTe 4 has a peak figure of merit (ZT) of 1.05 at 773 K and a desirable average ZT value of 0.84 in the temperature range of 400-773 K. Moreover, the thermoelectric performance of AgMnGeSbTe 4 can be further enhanced by precipitating of Ag 8 GeTe 6 , which acts as extra scatting centers for holes with low energy and phonons with medium wavelength. The simultaneous optimization in power factor and lattice thermal conductivity yields a peak ZT of 1.27 at 773 K and an average ZT of 0.92 (400-773 K) in AgMnGeSbTe 4 -1 mol% Ag 8 GeTe 6 .

Battery‐Driven N2 Electrolysis Enabled by High‐Entropy Catalysts: From Theoretical Prediction to Prototype Model

“…[3][4][5] This means that NH 3 is generally made in large, centralized facilities. In contrast, if NH 3 could be produced under less demanding conditions, there would be the potential for smaller devices to be used to generate NH 3 in a than five metal or metal cations with comparable ratios in the form of solid solutions, which can provide a large compositional space across various fields (such as, catalysis, [20,21] energy storage, [22,23] and thermoelectricity [24,25] ) due to almost infinite possible combinations of elements. [20,26] Since first reported Rost et al in 2015, [27] HEOs have been widely concerned in electrocatalysis field due to their multifarious redox behavior, diversiform cation compositions and large configurational entropy.…”

Maximizing phonon scattering efficiency by Cu2Se alloying in AgCuTe thermoelectric materials

“…According to the PGEC concept, researchers have conducted a lot of research to nd high-performance thermoelectric materials. In recent years, a series of high-performance thermoelectric materials conforming to the PGEC concept, such as clathrates, 9,10 Zintl phases, 11,12 and high entropy alloys, [13][14][15] have been extensively studied. Recently, a new class of (Ag, Cu) 2 X (X ¼ S, Se, Te)-based superionic conductors that exhibit excellent thermoelectric properties has been reported, [16][17][18][19] and the new concept "phonon-liquid electron-crystal" (PLEC) developed on the basis of the PGEC concept has been proposed to explain the structural properties of such superionic conductors.…”

Two-dimensional layered architecture constructing energy and phonon blocks for enhancing thermoelectric performance of InSb

“…The classic theory of phonon glass electron crystal (PGEC) provides a route to design a high-ZT thermoelectric material with higher electrical performance and low thermal conductivity. Therefore, numerous separate approaches have been devoted to optimizing the electrical and thermal properties, thus increasing the ZT value, and the electrical performance can be optimized via point defects (PDs) [13,14], band engineering [15,16], and high-entropy engineering [17,18]. In contrast, the microstructure engineering induced by nanocompositing [19,20], dislocations [21,22], and hierarchical architecture [23,24], has been employed and proven to be effective in reducing the thermal conductivity.…”