Engineering Lithium Storage in Silicon Carbide Monolayers through 585 Extended Line Defects.

Abstract

The development of advanced anode materials is essential to improve the performance of lithium−ion batteries (LiBs). In this work, silicon carbide (SiC) monolayers containing 585 extended line defects (585-ELDs) are investigated as potential anodes using ab initio density functional theory calculations. The influence of the inter-defect distance on structural stability, electronic properties, lithium adsorption, and diffusion mechanisms is systematically analyzed. By tuning the spacing between adjacent 585 extended line defects, Li adsorption and ionic transport can be significantly enhanced. Diffusion barriers of 0.34, 0.20, and 0.17 eV are obtained for the 7-, 3-, and 5-hex configurations, respectively, revealing a strong dependence of Li mobility on defect density and highlighting defect engineering as a promising strategy for optimizing SiC-based anodes. The open-circuit voltage (OCV) shows a strong dependence on the Li arrangement, reaching a maximum value of 0.86 V for the 5-hex system. In addition, the 3-hex structure presents a high theoretical storage capacity, nearly twice that of conventional graphite, highlighting the benefits of increased Li uptake. Overall, these findings demonstrate that tuning the density of extended line defects is an effective strategy to enhance Li storage and diffusion, positioning SiC monolayers as promising candidates for next-generation LiB anodes.