Synthesis, Structure, and Degenerate Semiconductor Behavior of Magnéli Phase Ti n O 2 n ‐1 Polycrystalline Ceramics

ABSTRACT Magnéli phases are a distinctive class of transition metal oxides with the general formula M n O 2 n ‐1 (M = Ti, W, Mo, or V;4 ≤ n ≤10). Owing to the characteristics of Ti 3d electronic orbitals and their unique crystallographic shear structures, Ti‐O Magnéli phase Ti n O 2 n ‐1 exhibits remarkable functional and have been widely utilized in batteries, catalysis, thermoelectric devices, and environmental technologies. Despite extensive investigations into their physicochemical properties, the intrinsic mechanical and electrical characteristics of Magnéli phase polycrystalline ceramics at room temperature remain insufficiently understood, which limits their development and application. In this study, various Magnéli phase Ti n O 2 n ‐1 powders and their corresponding ceramics were synthesized via titanium reduction reaction and hot‐pressing sintering. Their phase compositions, microstructures, mechanical properties, and electrical performances were systematically characterized. Electrical measurements revealed that Magnéli phase ceramics behave as degenerate semiconductors, exhibiting electrical conductivities of 10 1 –10 3 S·cm −1 , carrier mobilities of 10 1 –10 2 cm 2 ·V −1 ·s −1 , and carrier concentrations of 10 19 –10 21 cm −3 . Combined with density functional theory calculations on titanium oxides, the band structure and electronic behavior of the Magnéli phases were further clarified. The tunable band structure is a key advantage of Magnéli and related titanium oxide materials. This work provides insight into the intrinsic room‐temperature mechanical and electrical properties of Magnéli phase ceramics and offers a useful reference for their optimization and functional applications.