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Nuclear fusion energy holds great promise for being the ultimate solution to the ever-expanding energy needs of modern civilization. Based on the ideal operating temperature ranges of the plasma-facing armour materials and molten salt coolant in tokamak fusion reactors, there is a significant unutilized temperature gradient of ∼973–1273 K that can be potentially harvested by thermoelectric (TE) devices, without affecting the efficiency of the existing molten salt's heat cycle. In this review, we assess the potential suitability of various high temperature TE materials, such as Si1−xGex, n-type La3−xTe4, p-type Yb14(Mg,Mn)Sb11 zintl compounds, p-type B4C and other borides, for applications on plasma-facing surfaces of nuclear fusion reactors. The practical considerations of plasma-facing TE devices in fusion reactors were also discussed in detail, where potential overlaps between material modifications for enhancing TE properties and neutron irradiation resistance in materials were identified, together with compromises in TE device design parameters. Lastly, transverse TE materials, especially high temperature goniopolar Re4Si7 were also discussed in relation to their potential for Ettingshausen refrigeration for liquid He-free cooling of magnetic field coils. With the continued development of improved fusion reactor designs and structural materials, more opportunities for TE material applications are bound to open up, catalysing the advancement of TE material development for applications under extreme conditions. [ABSTRACT FROM AUTHOR]

Thermoelectric materials are highly promising for waste heat harvesting. Although thermoelectric materials research has expanded over the years, bismuth telluride‐based alloys are still the best for near‐room‐temperature applications. In this work, a ≈38% enhancement of the average ZT (300−473 K) to 1.21 is achieved by mixing Bi0.4Sb1.6Te3 with an emerging thermoelectric material Sb2Si2Te6, which is significantly higher than that of most BiySb2−yTe3‐based composites. This enhancement is facilitated by the unique interface region between the Bi0.4Sb1.6Te3 matrix and Sb2Si2Te6‐based precipitates with an orderly atomic arrangement, which promotes the transport of charge carriers with minimal scattering, overcoming a common factor that is limiting ZT enhancement in such composites. At the same time, high‐density dislocations in the same region can effectively scatter the phonons, decoupling the electron‐phonon transport. This results in a ≈56% enhancement of the thermoelectric quality factor at 373 K, from 0.41 for the pristine sample to 0.64 for the composite sample. A single‐leg device is fabricated with a high efficiency of 5.4% at ΔT = 164 K further demonstrating the efficacy of the Sb2Si2Te6 compositing strategy and the importance of the precipitate‐matrix interface microstructure in improving the performance of materials for relatively low‐temperature applications. [ABSTRACT FROM AUTHOR]

The crystal structure and transport properties of GeBi2Te4 are investigated as a layered compound with potential applications as thermoelectric materials. A disordered arrangement of Ge and Bi atoms in a septuple‐layer structure is discovered through synchrotron radiation X‐ray diffraction and transmission electron microscopy. Neutron pair distribution function analysis revealed the presence of discordant Ge atoms with an off‐centering distance of 0.12 Å at 300 K. The thermal conductivity of GeBi2Te4 is very low due to the strong phonon scattering. This is a result of the three Einstein local oscillators coupled with the disordered arrangement of atoms. This study also explores further the structural characteristics of these materials and their associated phonon scattering processes. The effect of Sb substitution for Ge on the electrical transport properties of the sample is profound, resulting in a change from p‐type to n‐type conduction. An enhanced thermoelectric figure of merit (ZT) of 0.45 at 523 K in the in‐plane direction is obtained. This research provides valuable insights into the crystal structure and transport properties of GeBi2Te4, showcasing its promising role as a thermoelectric material with potential for near‐room‐temperature applications. [ABSTRACT FROM AUTHOR]

A stable anode‐free lithium metal battery (AFLMB) is accomplished by the adoption of a facile fabricated amorphous antimony (Sb)‐coated separator (SbSC). The large specific surface area of the separator elevates lithium (Li)‐Sb alloy kinetic, improving Li wetting ability on pristine copper current collector (Cu). When tested with LiNi0.8Mn0.1Co0.1O2 (NMC811) as cathode, the full cell with SbSC demonstrates low nucleation overpotential with compact, dendrite‐free and homogeneous Li plating, and exhibits a notable lithium inventory retention rate (LIRR) of 99.8 % with capacity retention of 93.6 % after 60 cycles at 0.5 C‐rate. Conversely, full cells containing pristine separator/Cu (i. e., SC) and pristine separator/Sb‐coated current collector (i. e., SSbC) display poor cycling performances with low LIRRs. Density functional theory corroborates the nucleation behaviours observed during in‐situ half‐cell Li deposition. Functionalizing polymeric separator by metallic coating in AFLMB is a novel approach in improving the cycle life of an AFLMB by promoting homogeneous Li plating behavior. This innovative approach exemplifies a promising applicability for uniform Li‐plating behavior to achieve a longer cycle life in AFLMB. [ABSTRACT FROM AUTHOR]

Decades of studies on thermoelectric materials have enabled the design of high‐performance materials based on basic materials properties, such as bandgap engineering. In general, bandgap energies correspond to the temperature at which the peak thermoelectric performance occurs. For instance, CuGaTe2 with a relatively wide bandgap of 1.2 eV has its peak zT > 1 at > 900 K. On the other hand, the zT is usually very low (<0.1) for this material at room temperature. This severely limits its average zT and hence overall performance. In this study, a phase diagram‐guided Sb alloying strategy to improve the low‐temperature zT of CuGaTe2 is used, by leveraging on the solubility limits to control the formation of the microstructural defects. The addition of Sb simultaneously improves the electrical conductivity and decreases the lattice thermal conductivity. For a low‐temperature range of 300–623 K, this Sb‐alloying strategy enables the achievement of a record high average zT of 0.33. The strategy developed in this study targets the improvement of the low‐temperature range of CuGaTe2, which is rarely focused on for wide‐bandgap ABX2 compounds, opening up more opportunities for holistic performance improvements, potentially enabling ultrahigh‐performance thermoelectrics over a wide temperature range. [ABSTRACT FROM AUTHOR]

Doping usually reduces lattice thermal conductivity because of enhanced phonon-impurity scattering. Here, we report unexpected doping effects on the lattice thermal conductivity of quasi-one-dimensional (quasi-1D) van der Waals (vdW) TiS3 nanoribbons. As the nanoribbon thickness reduces from ~80 to ~19 nm, the concentration of oxygen atoms has a monotonic increase along with a 7.4-fold enhancement in the thermal conductivity at room temperature. Through material characterizations and atomistic modellings, we find oxygen atoms diffuse more readily into thinner nanoribbons and more sulfur atoms are substituted. The doped oxygen atoms induce significant lattice contraction and coupling strength enhancement along the molecular chain direction while have little effect on vdW interactions, different from that doping atoms induce potential and structural distortions along all three-dimensional directions in 3D materials. With the enhancement of coupling strength, Young's modulus is enhanced while phonon-impurity scattering strength is suppressed, significantly improving the phonon thermal transport. Doping generally hinders phonon transport. Here, authors significantly increase the thermal conductivity of TiS3 nanoribbons through doping, originating from the intensified bonding strength along the molecular chain direction without distorting the one-dimensional structure induced by doped atoms. [ABSTRACT FROM AUTHOR]