[en] Nanocomposite is proved to be an effective method to improve thermoelectric performance. In the present study, graphene is introduced into p-type skutterudite La_0.8Ti_0.1Ga_0.1Fe₃CoSb₁₂ by plasma-enhanced chemical vapor deposition (PECVD) method to form skutterudite/graphene nanocomposites. It is demonstrated that the graphene has no obvious effect on the electrical conductivity of La_0.8Ti_0.1Ga_0.1Fe₃CoSb₁₂, but the Seebeck coefficient is slightly improved at high temperature, thereby leading to high power factor. Furthermore, due to the enhancement of phonon scattering by the graphene, the lattice thermal conductivity is reduced significantly. Ultimately, the maximum zT value of La_0.8Ti_0.1Ga_0.1Fe₃CoSb₁₂/graphene is higher than that of graphene-free alloy and reaches to 1.0 at 723 K. Such an approach raised by us enriches prospects for future practical application. (paper)

[en] To achieve the commercial application of high-performance skutterudite (SKD) thermoelectric (TE) devices, breakthroughs in the batch fabrication of TE material and the realization of its stable bonding to the barrier layer are necessary. In this work, the large-scale SKD bulks with excellent TE performance and decent homogeneity are prepared by melt-spinning (MS) combined with a hot pressing process. Then, a modified two-step sintering method is employed to effectively suppress the degree of initial interfacial reaction, resulting in a barrier layer/SKD joint that exhibits low contact resistivity (≈2µΩ·cm${}^2$) and high bonding strength (≈30 MPa) with no significant change after aging at 773 K for 30 days. Encouragingly, the joints welded with Mo${}_{50}$Cu${}_{50}$ electrodes also show high stability under the same aging conditions. Finally, the as-fabricated 8-pair module shows a highly competitive conversion efficiency of 9% under a temperature difference of 580 K. In addition, during a 360 h aging test with hot-side temperature of 773 K, the module shows excellent stability. Overall, this work paves the way for batch fabrication of high-performance SKD using MS and lays a solid foundation for the stable operation of SKD-based modules. (© 2024 Wiley‐VCH GmbH)

[en] Highlights: • The competitive oxidation of MoSi₂ and WB inhibits the formation of Mo-containing oxides. • The addition of WB is beneficial to the decrease of surface temperature, and then stabilize the existence of intermediate MoB. • The ablation mechanism of the ZMW coating was also analyzed based on thermodynamics predictions. Improving the long time ablation resistance of thermal protective coating is the key index to promote the development of hypervelocity aerocrafts. In this work, the ablation behaviors of ZrB₂-MoSi₂ and ZrB₂-MoSi₂-WB composite coatings fabricated by vacuum plasma spray (VPS) were evaluated by plasma flame. The microstructure evolution induced by prolonged ablation was focused on and discussed in detail. The results shows that the addition of WB significantly improved the long-term ablation resistant performance of the ZrB₂-MoSi₂ coating, as characterized by integrated macrostructure, compact microstructure and decreased thickness of oxide layer. The function of WB was explained in detail based on microstructure observation and thermodynamic calculations, which would give some inspirations for the design of UHTCs.