Thermoelectric Cu–S-Based Materials Synthesized via a Scalable Mechanochemical Process

Abstract

In this work, Cu based sulfides (chalcopyrite CuFeS 2, mohite Cu 2 SnS 3, tetrahedrite Cu 12 Sb 4 S 13 , mawsonite Cu 6 Fe 2 SnS 8 and kesterite Cu 2 ZnSnS 4 ) were synthesized by industrial milling in an excentric vibration mill to demonstrate scalability of their synthesis. For comparison, laboratory scale milling in a planetary mill was performed. The properties of the obtained samples were characterized by X-ray diffraction, and in some cases, also by Mössbauer spectroscopy. For densification of powders the method of Spark Plasma Sintering was applied to prepare suitable samples for thermoelectric (TE) characterization which created the core of this paper. Comparison of the figure-of-merit ZT, representative of the efficiency of thermoelectric performance, show that the scaling process of mechanochemical synthesis leads to the similar values than using laboratory methods. This makes the cost effective production of Cu-based sulfides as prospective energy materials for converting heat to electricity feasible. Several new concepts have been developed involving combinations of natural and synthetic species (tetrahedrite) and nanocomposite formation (tetrahedrite/digenite, mawsonite/stannite) offer sustainable approaches in solid state chemistry. Mechanochemical synthesis is selected as a simple, one-pot and facile solid-state synthesis of thermoelectric materials with the capability to reduce, or even eliminate solvents, 3 toxic gases, high temperatures with controllable enhanced yields. The synthesis is environmentally friendly and essentially waste-free. The obtained results illustrate the possibility of large-scale deployment of energy-related materials.

Effects of Grain Size on the Thermoelectric Properties of Cu2SnS3: An Experimental and First-Principles Study

“…In addition, milling offers the advantage of facile and scalable production for industrial use. 9 The energy conversion efficiency of a TE material is determined by a dimensionless figure of merit (zT) expressed as zT = S 2 /ρκ*T, where S, ρ, κ, and T are the Seebeck coefficient, electrical resistivity, thermal conductivity, and absolute temperature, respectively. S 2 /ρ is referred to as the power factor (PF).…”

“…Furthermore, a highly dense disordered CTS polymorph can be stabilized without any chemical substitution. 9 The present work aims to shed light on the degenerate semiconductor-like behavior of nanocrystalline CTS samples. Three dense CTS samples were produced using powder synthesized by high-energy reactive ball milling and SPS.…”

Ternary and Quaternary Nanocrystalline Cu-Based Sulfides as Perspective Antibacterial Materials Mechanochemically Synthesized in a Scalable Fashion

“…The mechanochemical syntheses of ternary and quaternary Cu sulfides represent an excellent scalable method to obtain a predetermined Cu–sulfide phase. 63 , 65 In general, all samples were composed of the desired ternary or quaternary copper sulfide as a major phase. However, secondary phases were also present either as a result of an incomplete reaction between the initial reactants or because of the fact that they represent intermediate phases formed on the reaction pathway to the desired compound.…”

“…The details on the mechanochemical syntheses of the majority of the studied compounds can be found in the following publications: mawsonite Cu 6 Fe 2 SnS 8, 58 rhodostannite Cu 2 FeSn 3 S 8, 59 kesterite Cu 2 ZnSnS 4, 60 , 65 tetrahedrite Cu 12 Sb 4 S 13, 61 colusite Cu 13 VSn 3 S 16, 62 mohite Cu 2 SnS 3, 63 and famatinite Cu 3 SbS 4. 64 The weights of precursors for all the compounds (including those newly prepared) and the corresponding milling time are provided in Table 1 .…”

Paving the Way to Establish Protocols: Modeling and Predicting Mechanochemical Reactions

“…Besides, mechanochemistry is capable of inducing high-temperature reactions at room temperature, 4 surpassing certain solubility limit issues, 5,6 obtaining metastable phases, 7,8 or promoting the scaling up of reactions. 9 Nevertheless, the most important feature of mechanochemistry is its ability to induce chemical reactions without the need of solvents, restricting the generation of toxic byproducts and, therefore, awarding it the label of a green synthetic procedure. 3,10,11 In spite of the extended use of mechanochemistry, the understanding of its foundations is quite limited.…”