Enhancing the thermoelectric properties of single and double filled p-type skutterudites synthesized by an up-scaled ball-milling process

Abstract

The single and double filled p-type skutterudites Ce 0.8 Fe 3 CoSb 12 and Ce 0.5 Yb 0.5 Fe 3.25 Co 0.75 Sb 12 have been prepared by mechanical alloying. This offers a rapid method for the preparation of skutterudites that could be scaled up for adoption at industrial level. The large-scale samples prepared by ball-milling exhibit enhanced figures of merit ZT, compared with materials prepared by conventional solid-state reaction. At room temperature ZT is increased by ca. 19 % for both single and double filled skutterudites. Maximum figures of merit, ZT = 0.68 and ZT = 0.93 are attained for Ce 0.8 Fe 3 CoSb 12 at 773 K and Ce 0.5 Yb 0.5 Fe 3.25 Co 0.75 Sb 12 at 823 K respectively. The improvement in thermoelectric values at room temperature may be traced to a reduction in thermal conductivity in the ball-milled samples arising from the reduced grain size. The influence of the microstructure on the thermoelectric properties, together with the stability in air and the performance of the materials after several heating and cooling cycles has been studied and are detailed in this work. The densified samples prepared by ball-milling also show a higher resistance to oxidation, which starts at 694 K for Ce 0.8 Fe 3 CoSb 12 and at 783 K for Ce 0.5 Yb 0.5 Fe 3.25 Co 0.75 Sb 12 .

Thermoelectrics: From history, a window to the future

“…For example, as a way to increase the filling factors of skutterudites, techniques such as high-pressure sintering (HPS) or high pressure-high temperature (HPHT) using diamond anvil cells (DACs) are shown to be good alternatives. [302,[326][327][328][329][330][331][332][333][334] In some occasions, these methods are also used in combination with non-equilibrium syntheses such as melt spinning R y Co 4 Sb 12 (R = Nd, Sm, Gd, Tb, and Dy with zTs up to 1.3) or super-cooling reaching the same zT for R y Co 4 Sb 12 (R = Ce, Ca, Nd, Sm, Gd, Yb, Dy).…”

Modelling a Segmented Skutterudite-Based Thermoelectric Generator to Achieve Maximum Conversion Efficiency

“…TE materials are being synthesized via different methods, such as microwave-assisted thermolysis [17], mechanical alloying [5,23,24], solvo-thermal [25], fast quenching methods [23], nanocrystal synthesis [26][27][28], melting and annealing [29,30], and solid-state reaction [23,31]. In this study, the skutterudite materials were prepared via melting and annealing, bismuth telluride was prepared via a chemical synthesis route, and antimony telluride was prepared via physical vapor deposition followed by spark plasma and/or hot press methods [3,[32][33][34].…”

“…In this study, the skutterudite materials were prepared via melting and annealing, bismuth telluride was prepared via a chemical synthesis route, and antimony telluride was prepared via physical vapor deposition followed by spark plasma and/or hot press methods [3,[32][33][34]. Irrespective of the method of preparation chosen, characterization processes, such as Scanning Electron Microscopy [5,35], Transmission Electron Microscopy [36,37], and X-ray Powder Diffraction [38,39], are carried out on the dried powders. Scanning Electron Microscopy (SEM) is for the analysis of surface topography and the composition of the samples.…”

“…A reduction in these losses will give rise to an increase in the figure of merits. To date, various TE materials, such as skutterudite [3][4][5][6], clathrate [7][8][9], half heusler [10][11][12], metal oxides [13,14], perovskite [15,16], and chalcognide [17,18], have been studied. Different material approaches have proven promising in increasing the ZT of materials; such approaches include Phonon Glass Electron Crystals (PGECs) [19], Phonon Liquid Electron Crystals (PLECs) [20], and the use of band resonant states to enhance the density of states [2], etc.…”

High thermoelectric performance of rapidly microwave-synthesized Sn1−δS

“…Among these methods, ballmilling, arc-melting and high-pressure synthesis have become attractive alternatives for the preparation of thermoelectric materials. [41][42][43][44][45][46] In the present work, we would like to emphasize that microwave-assisted synthesis is also a powerful method to consider. This is a ''Fast Chemistry'' method that has not been extensively studied for the preparation of thermoelectric materials yet, [47][48][49] but has emerged for the synthesis of a plethora of other non-molecular materials (especially oxides) with different structures, properties and applications.…”