Novel two-dimensional tetragonal vanadium carbides and nitrides as promising materials for Li-ion batteries

• Published in: Physical chemistry chemical physics : PCCP 2019-09, Vol.21 (35), p.19513-1952
• Main Authors: Wu, Yi-Yuan, Bo, Tao, Zhang, Junrong, Lu, Zhansheng, Wang, Zhiguang, Li, Yuhong, Wang, Bao-Tian
• Format: Article
• Language: English
• Subjects: Adsorption; Anodes; Charge density; Circuits; Commercialization; Configurations; Diffusion barriers; Dispersion curve analysis; Electrode materials; Energy storage; First principles; Free energy; Lithium; Lithium-ion batteries; Metal carbides; Monolayers; Nitrides; Rechargeable batteries; Sheets; Substrates; Transition metals; Two dimensional materials
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c9cp03954f

Two-dimensional (2D) materials, owing to their unique properties, have shown great potential for energy storage. In this work, we predict two types of new 2D transition metal carbides and nitrides, namely, tetragonal V 2 C 2 and V 2 N 2 (tetr-V 2 C 2 and tetr-V 2 N 2 ) monolayer sheets. Comprehensive first-principle calculations show that these two 2D systems exhibit dynamic (thermal) stabilities and intrinsic metallic nature. Compared with the commercialized graphite anode material, tetr-V 2 C 2 and tetr-V 2 N 2 monolayer sheets exhibit lower Li diffusion barrier of 89 and 94 meV, higher theoretical capacity of 412 and 425 mA h g −1 and lower average open circuit of 0.468 and 0.583 V, respectively. Combining those advanced features, our proposed tetr-V 2 C 2 and tetr-V 2 N 2 monolayer sheets are both promising candidates as anode materials for lithium-ion batteries (LIBs) in the future. We demonstrate that tetr-V 2 C 2 and tetr-V 2 N 2 monolayer sheets exhibit low Li diffusion barrier, high theoretical capacity and low average open circuit, suitable as anode materials for lithium ion batteries.