Economical and Facile Route to Produce Gram-Scale and Phase-Selective Copper Sulfides for Thermoelectric Applications

Abstract

Producing thermoelectric materials without energy-intensive processes is essential to reduce the production costs and for wide-scale applications. Copper sulfides have recently been identified as new and promising environmentally friendly thermoelectric materials. Here, an economical synthetic route for the gram-scale preparation of copper sulfide is developed that enables selective control of the copper oxidation state, in turn allowing the stoichiometry to be tuned to optimize the thermoelectric characteristics of the product. Through this facile and scalable protocol, CuS, Cu 1.75 S, Cu 1.80 S, and Cu 2 S powders have been synthesized in conjunction with X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy to verify the stoichiometry of each material. The as-prepared compounds were further characterized by thermoelectric measurements and the performance of a test generator module containing ten p-type Cu 2 S legs was subsequently investigated. Upon heating one side of the module to 70 °C, the device produced an output voltage of 30.9 mV and a corresponding power output of 3.4 μW, which is comparable to the power outputs of many of devices fabricated with expensive and toxic thermoelectric elements. This work presents a novel pathway for the development of low-cost thermoelectric devices by introducing a facile, tunable, and high-yield Cu x S synthesis procedure that may be readily adapted to other metal sulfides.

Sensors-on-paper: Fabrication of graphite thermal sensor arrays on cellulose paper for large area temperature mapping

“…Further, the existing thermoelectric energy conversion devices/generators are usually manufactured from toxic and expensive semiconductors such as bismuth tellurides, led tellurides, and their alloys [26] , [27] , [28] . Therefore, the current thermoelectric research is focused on finding low-cost and non-toxic thermoelectric conductors for the application [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] . With some improvements and modifications in the thermoelectric properties of graphite such as by organic doping or alloying with other semiconductors, they can also be utilized in the fabrication of thermoelectric devices [19] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] .…”

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.…”

Core–shell nanostructures for better thermoelectrics

“…13 Over the past few decades, great progress has been achieved in finding new and structural thermoelectric materials. Materials such as (Bi,Sb) 2 (Te,Se) 3 , 34 Pb(Te,Se,S), 35,36 SnSe, [37][38][39] SiGe, 40,41 Cu 2 -(Se,S,Te), [42][43][44][45][46][47] clathrates, 48 skutterudites, 49 Heusler alloys 50,51 are some of the high zT candidates. 12 Recent studies also show that significant enhancements in zT are achieved by reducing the thermal conductivity via the introduction of additional phonon scattering regions in bulk materials.…”