Synergistic modulation of the thermoelectric performance of melt-spun p-type Mg₂Sn via Na₂S and Si alloying

Abstract

Mg2Sn, comprising low-cost, Earth-abundant and environmentally-friendly elements, is a promising candidate for thermoelectric applications at medium temperature range. In contrast to the well-developed high-performance n-type Mg2Sn materials, the thermoelectric performance...

Enhanced thermoelectric performance of p-type Mg2Sn single crystals via multi-scale defect engineering

“…The Hall coefficient R H was measured at RT by sweeping a magnetic eld from −5.0 T to 5.0 T using a physical properties measurement system (PPMS, Quantum Design). The carrier 25 SC/p-type 5.92 × 10 19 101 Sn Ag (0.5%) 5 Large-grain PC/p-type 5.9 × 10 19 ∼130 Mg + MgAg eutectic microstructures Li (2%) 19 PC/p-type 2.37 × 10 20 77 Not reported Li (2.5%) 20 PC/p-type 3.1 × 10 20 69 Sn, MgO Na (2.5%) 20 PC/p-type 1.1 × 10 20 82 Sn, MgO, t-Mg 9 Sn 5 + o-Mg 2 Sn Na (7%) 30 PC/p-type 1.1 × 10 20 69 -concentration n was obtained by n = j1/(eR H )j, and the Hall carrier mobility m H was calculated by m H = sR H , where e is the electric charge and R H is the Hall coefficient. The typical sample size used for the S and s measurements was 2.5 × 2.5 × 8 mm 3 , and that for the Hall measurements was 2.5 × 6 × 0.8 mm 3 .…”

“…35,36 On the contrary, p-type Mg 2 Sn has inferior TE properties for practical applications. Various elements such as Ag, 5 Li, 19,20 Ga, 25 Cu, 29 and Na 30 were used to introduce hole carriers into Mg 2 Sn. Many efforts have been devoted to enhancing the TE performance of p-type Mg 2 Sn.…”

“…Among the considered materials, Mg 2 Sn and its derivatives Mg 2 (Si,Ge,Sn) are potential TE materials for operation at moderate temperatures between 400 K and 800 K. 5–34 Good TE performances ( zT ∼ 0.9 at 750 K) have been reported for n-type Mg 2 Sn utilizing point defects and carrier optimization. 26,27 Among the n-type Mg 2 Sn samples, undoped, B-doped, and Sb-doped Mg 2 Sn single crystals (SCs), 22–24,34 Bi-doped Mg 2 Sn polycrystals (PCs), 26 and Sb-doped Mg 2 Sn PCs 27 prepared by applying physical and chemical pressure were found to contain Mg vacancy (V Mg ) as a point defect.…”

“…Crystallinity/conduction type, carrier concentration n, carrier mobility m H , and existing secondary phase(s) of the prepared Mg 2−x Li x Sn ingots and previously reported Mg 2 Sn-based samples 5,19,20,25,30. The abbreviations SC and PC stand for 'single crystal' and 'polycrystal', respectively…”

Re-envisioning the Key Factors of Magnesium Metal Anodes for Rechargeable Magnesium Batteries

“…Examples include the uneven Mg plating, Mg dendrites growth, abnormal self-accelerating pit growth stripping, etc. , Moreover, there is still no efficient, practical, and high-quality Mg foil manufacturing process to match the current cathode materials and RMBs utilizations. Owing to the poor manufacturing capability of pure Mg, currently ultra-thin pure Mg foils (<100 μm) are usually prepared by melt-spinning, rapid solidification, hot-rolling, etc., − yet those methods are unsuitable for practical applications due to issues of low efficiency, low yield, easy oxidation, and difficulty to control accuracy. Manufacturing processes deserve more in-depth consideration in order to extract their full value and ultimately advance the field of RMBs.…”