Graphitic Sic: A Potential Anode Material For Na-Ion Battery With Extremely High Storage Capacity

Bulk SiC phases with tetrahedral arrangements have been identified several decades ago, and have been widely studied due to their potential applications. Until recently, Yaghoubi et al.'s experiment (Chem. Mater. 2018, 30, 7234) observed the existence of graphitic SiC with few SiC layers stacking, which implies the possible synthesis of such material in the future. In this work, we explored the potential application of graphitic SiC as the Na-ion battery anode via the first-principle simulation. Our results reveal that the theoretical capacity of graphitic SiC reaches up to 1339.44 mAh/g, which is almost the highest among the already known Na-ion battery anodes. Together with the low diffusion barrier, moderate open circuit voltage and excellent electronic conductivity during the sodiation, we propose that the graphitic SiC is a potential material as Na-ion battery anode. More importantly, we find that the intercalation strength of Na ions into C-based multilayer materials (or the corresponding theoretical capacity, the operation voltage) could be enhanced by increasing the amount of covalent components in Na-C bonds, which could be realized via doping by atom (such as Li, Be, B, Al, Si or P) with lower electronegativity than that of C atom.