Mechanically robust, self-healing graphene like defective SiC: A prospective anode of Li-ion batteries

Abstract

First-principles density functional theory (DFT) computations are carried out to assess the potential application of a monolayer Silicon carbide (SiC) with the presence of topological and point defects. Results show that the unstable binding of pristine SiC makes it a poor candidate for the anode material. However, the introduction of vacancy and Stone-Wales type topological defect in SiC possesses a stable Li binding property. Besides, all the defective configuration showed higher electrical conductivity, superior mechanical robustness and stable formation energy. We also observed a structural reorientation from point to topological defect with a 5-8-5 ring formation in C and Si-C bi-vacancy and a Li-mediated phenomenon in the case of Si bi-vacancy. All the configurations under consideration exhibited low open-circuit voltage (0.1 V), a low Li diffusion barrier (~0.77 eV), and a fairly high specific capacity (501 mAh/g for Stone-Wales) compared to the conventional graphite anode. Besides, the ab initio molecular dynamics calculations confirmed the thermal stability and structural integrity of the defective SiC. Based on these findings, the present study suggests that SiC with a Stone-Wales defect can be a forthcoming candidate for the anode of LIBs. © 2020 Elsevier B.V.