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Mechanically robust, self-healing graphene like defective SiC: A prospective anode of Li-ion batteries
Applied Surface Science ( IF 6.7 ) Pub Date : 2021-03-01 , DOI: 10.1016/j.apsusc.2020.148417
M.S. Manju , Siby Thomas , Sang Uck Lee , Ajith Kulangara Madam

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 be a forthcoming candidate for the anode of LIBs.

中文翻译:

机械坚固、自修复石墨烯,如有缺陷的 SiC:锂离子电池的预期阳极

摘要 进行第一性原理密度泛函理论 (DFT) 计算以评估存在拓扑缺陷和点缺陷的单层碳化硅 (SiC) 的潜在应用。结果表明,原始 SiC 的不稳定结合使其成为负极材料的不良候选者。然而,在 SiC 中引入空位和 Stone-Wales 型拓扑缺陷具有稳定的锂结合性能。此外,所有有缺陷的构型都显示出更高的导电性、优异的机械强度和稳定的形成能。我们还观察到从点到拓扑缺陷的结构重新定向,在 C 和 Si-C 双空位中形成 5-8-5 环,并在 Si 双空位的情况下观察到 Li 介导的现象。考虑中的所有配置都表现出低开路电压(0.1 V),与传统的石墨负极相比,Li 扩散势垒低(~0.77 eV)和相当高的比容量(Stone-Wales 为 501 mAh/g)。此外,从头算分子动力学计算证实了有缺陷的 SiC 的热稳定性和结构完整性。基于这些发现,本研究表明具有 Stone-Wales 缺陷的 SiC 是即将成为 LIB 阳极的候选材料。
更新日期:2021-03-01
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