Enhanced Thermoelectric Performance of SnTe-Based Materials via Interface Engineering

Abstract

Interface engineering has been regarded as an effective strategy to improve thermoelectric (TE) performance by modulating electrical transport and enhancing phonon scattering. Herein, we develop a new interface engineering strategy in SnTe-based TE materials. We first use a one-step solvothermal method to synthesize SnTe powders decorated by Sb2Te3 nanoplates. After subsequent spark plasma sintering, we found that an ion-exchange reaction between the Sb2Te3 and SnTe matrixes happens to result in Sb doping and the formation of SnSb nanoparticles and the recrystallization of the nanograined SnTe at the grain boundaries of the SnTe matrix. Benefitting from this unique engineering, a significantly reduced lattice thermal conductivity of ∼0.64 W m–1 K–1 and a high zT of ∼1.08 (∼100% enhanced) at 873 K are achieved in SnTe–Sb0.06. Such improved TE properties are attributed to the optimized carrier concentration and valence band convergence due to the Sb doping and enhanced phonon scattering by interface engineering at the grain boundaries. This work has demonstrated a facile and effective method to realize high-TE-performance SnTe via interface engineering.

Pushing the limit of synergy in SnTe-based thermoelectric materials leading to an ultra-low lattice thermal conductivity and enhanced ZT

“…On the other hand, nanostructuring and phonon glass-electron crystals are critical for reducing thermal conductivity. 19–22…”

“…17,18,27–33 Defect engineering through microstructure scale control, lattice strains, interface engineering, and soft phonon modes, among others, have been shown to effectively scatter phonons leading to low thermal conductivity values. 20,34–40 Most recently, the possibility of n-type SnTe has been reported, thus enhancing the possibility of fabrication of a homogeneous thermoelectric device. 41,42…”

Comprehensive Insights into Synthesis, Structural Features, and Thermoelectric Properties of High-Performance Inorganic Chalcogenide Nanomaterials for Conversion of Waste Heat to Electricity

“…Recent progress has resulted in a high ZT value of about 2 with a projected efficiency of 20%, which is expected to have a significant impact on the energy production and conservation sectors . Currently, TE materials that are of keen interest are Bi 2 Te 3 ; PbTe; Bi 2 Se 3 ; PbSe; SnTe; Ge 0.95 Bi 0.05 Te; Ge 1– x – y Ta x Sb y Te; half-Heusler compounds like Ti x (Zr 0.5 Hf 0.5 ) (1– x ) NiSn ( x = 0–0.7) or BXGa (X = Be, Mg, and Ca); skutterudites; Mg 2 X (X = Si, Ge, and Sn); ternary compounds (e.g., MgAgSb and BiCuSeO), binary compoundsoxides like ZnO, SrTiO 3 , or NaCo 2 O 4 ; and nitrides like BN, copper chalcogenides, ScN, or C 3 N 4 ; etc.…”

Role of Deep Defects on the Transport Properties of Polycrystalline Thermoelectric Alloys and Composites

“…Conventional zone-melted solidification of ternary p-type (Bi 1-x Sb x ) 2 Te 3 and n-type Bi 2 (Te 1-y Se y ) 3 single crystals have been recognized for their valuable properties at least since the late 1950s. 1 They are among the highest performing bulk materials for thermoelectric applications below 500 K. There is a recently renewed interest in their development in polycrystalline form in order to improve their performance [2][3][4][5][6][7] for industrial applications. They have been synthesized in various forms and are frequently compacted by spark plasma sintering for both cooling and energy conversion applications near room temperature.…”