Designing Layered TaC for Superdense Li ⁺ Storage

Layered anodes with high initial Coulombic efficiency (ICE), high tap density, elevated volumetric energy density, and low production cost have attracted considerable attention for lithium-ion (Li + ) storage. In contrast to two-dimensional (2D) anodes, the ultrahigh valence state of tantalum (Ta, +5) and its large ionic radius make layered Ta-based compounds promising hosts for accommodating large amounts of Li + . In this study, we employ density functional theory (DFT) to investigate three types of layered Ta-based materials (TaC, TaN, and TaB) as potential anodes for the first time. Among them, layered TaC is identified as a highly promising host for superdense Li + storage. To the best of our knowledge, layered TaC delivers the highest specific capacity (above 900 mAh g –1 ) and energy density 433.35 Wh kg –1 (3293.46 Wh L –1 ) reported to date among layered anodes. Moreover, the moderate average voltage of 0.7 V ensures safety. Furthermore, it exhibits a low Li + diffusion barrier of 0.304 eV, suggesting excellent rate performance. These results highlight the remarkable superdense Li + storage capability of layered TaC and underscore its strong potential for commercialization.