Thermoelectric Cu₁₂Sb₄S₁₃‐Based Synthetic Minerals with a Sublimation‐Derived Porous Network

Abstract

Pores in a solid can effectively reduce thermal conduction, but they are not favored in thermoelectric materials due to simultaneous deterioration of electrical conductivity. Conceivably, creating a porous structure may endow thermoelectric performance enhancement provided that overwhelming reduction of electrical conductivity can be suppressed. This work demonstrates such an example, in which a porous structure is formed leading to a significant enhancement in the thermoelectric figure of merit (zT). By a unique BiI3 sublimation technique, pore networks can be introduced into tetrahedrite Cu12Sb4S13‐based materials, accompanied by changes in their hierarchical structures. The addition of a small quantity of BiI3 (0.7 vol%) results in a ≈72% reduction in the lattice thermal conductivity, whereas the electrical conductivity is improved due to unexpected enhanced carrier mobility. As a result, an enhanced zT of 1.15 at 723 K in porous tetrahedrite and a high conversion efficiency of 6% at ΔT = 419 K in a fabricated segmented single‐leg based on this porous material are achieved. This work offers an effective way to concurrently modulate the electrical and thermal properties during the synthesis of high‐performance porous thermoelectric materials.

High ZT in p-type thermoelectric (Bi,Sb)2Te3 with built-in nanopores

“…S3, ESI†) may have disturbed the MAed powders from contacting each other during SPS. 58 Because of the low reaction efficiency of the MA process as well as the low solubility limit of BiI 3 in (Bi,Sb) 2 Te 3 , 59 BiI 3 might not fully react during the MA process. During SPS, the heating rate was so fast that BiI 3 did not have enough time to escape when the MAed powder began to react.…”

“…S3, ESI †) may have disturbed the MAed powders from contacting each other during SPS. 58 Because of the low reaction efficiency of the MA process as well as the low solubility limit of BiI 3 in (Bi,Sb) 2 Te 3 , 59 BiI 3 might not fully react…”

Cryogenic thermoelectric enhancements in SbCl3-doped porous Bi0.85Sb0.15 alloys

“…The studies reported by Khan et al 28 and Hopkins et al 29 indicate that the nano/microscale hierarchical pores and orderly aligned pores can scatter a wide spectrum of phonons and result in a lower κ L . Various methods are proposed to fabricate the porous TE materials, such as template elimination, 30–33 chemical synthesis, 27,34,35 solid-state explosive reactions, 36 3D printing, 37 etc. Although a porous structure can lower the κ L , its effect may be counterbalanced by the deterioration of σ due to carrier scattering by the pores, which results in the decrease of ZT .…”

“…BiI 3 and SbI 3 ) are commonly used to fabricate porous TE materials due to their volatility and doping effects on modulating the electronic properties. 32,38,39 Herein, the Bi 0.85 Sb 0.15 alloy was selected as the host material and SbCl 3 with a low sublimation temperature of 496 K was selected as the pore template. The Bi 0.85 Sb 0.15 / x vol% SbCl 3 materials were prepared by melt-spinning combined with hot pressing and annealing, and their cryogenic TE properties were investigated.…”

Phase Analysis and Thermoelectric Properties of Cu-Rich Tetrahedrite Prepared by Solvothermal Synthesis

“…They also possess excellent features for widespread commercial use, such as non-toxicity and low price caused by high abundance [30]. Within the promising sulfide-based thermoelectrics, there are also materials that crystallize in the tetrahedrite-type structure [25,31,32]. The early investigation of the naturally-occurring Cu 12 Sb 4 S 13 mineral has opened a large playground for this promising family of compounds [33,34].…”