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Li3TaO4 with a high melting point, good thermal stability, and higher lithium content has become a possible choice for breeder materials, which have potential applications in future fusion reactors. Perfect and defect crystal models of Li3TaO4 are set up, and all of the tritium-diffusion pathways have been studied by the first-principles method. The activation energy barriers of different diffusion pathways are calculated and analyzed considering the pathway length and tritium–oxygen interactions. The obtained minimum energy barrier for tritium diffusing in the perfect Li3TaO4 crystal is only 0.34 eV. The minimum energy barrier is less than 0.72 eV when tritium diffuses in the defect Li3TaO4 crystal in the presence of a lithium vacancy. Finally, the diffusion coefficients of tritium in the Li3TaO4 crystal are calculated, which further confirm that it is easy for tritium to escape from the trap of the lithium vacancy and diffuse in the crystal. Such a tritium-diffusion behavior is in favor of the tritium-release process of the Li3TaO4 crystal and could provide theoretical guidance for the future applications of Li3TaO4 materials.

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The preparation and performance improvement of the spinel coating on the surface of ferritic alloy is of wide interest for its application in the metallic interconnects of the solid oxide fuel cells (SOFCs). The CoMn2O3 composite coating is prepared on the surface of the Crofer alloy by the composite electrodeposition method. A step‐heating thermal conversion process is subsequently used to convert the composite coating into a spinel coating, while a direct‐heating process is implemented as the control experiment. Isothermal oxidation tests are then carried out for the prepared samples in order to present the high temperature performance. Scanning electron microscopy (SEM), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and area‐specific resistance (ASR) are used to analyze the properties of the matrix and coatings. The experimental results reveal that the coatings by step‐heating thermal conversion exhibit better performance of electrical conductivity and oxidation resistance than the coatings by direct‐heating process. Furthermore, with the increase of oxidation time, the atomic proportion of Cr element diffusing to the surface of the matrix is maintained at about 3%–4% for the samples with spinel coatings by step heating, which effectively prevent the Cr volatilization in the matrix. The preparation of spinel coatings on the ferritic alloy by composite electrodeposition and step‐heating thermal conversion is helpful to stimulate new ideas for the development of reliable and cost‐effective metallic interconnect.