Theoretical investigations of TiNbC MXenes as anode materials for Li-ion batteries

• Published in: Journal of alloys and compounds 2019-03, Vol.778, p.53-60
• Main Authors: Li, Ya-Meng, Chen, Wan-Gao, Guo, Yong-Liang, Jiao, Zhao-Yong
• Format: Article
• Language: English
• Subjects: Adsorption; Anodes; Diffusion barriers; Double-metal MXenes; Electrochemical analysis; Electrochemical properties; Electrode materials; Electronic properties; First-principles calculation; Li-ion battery; Lithium-ion batteries; Monolayers; MXenes; Niobium carbide; Rechargeable batteries; Ring structures; TiNbC; Titanium
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.11.140

The electronic properties and electrochemical performance of double-metal MXenes: TiNbC and TiNbCT2 (T = O, F and OH) as anode materials for Li-ion batteries (LIBs) have been studied to understand the effects of Nb(Ti)-layer inserting in Ti2C (Nb2C) monolayer and terminated functional-group (T = O, F, and OH) on the electrochemical performance. The results demonstrate that all the TiNbC and TiNbCT2 monolayers are metallic conductivity, while the adsorption of lithium-ion on TiNbC(OH)2 is unstable, and TiNbCF2 is unfavorable as anode material for LIBs due to the F-groups and Li-ions forming ring structure. Specifically, TiNbC and TiNbCO2 nanosheets exhibit such distinctive features as moderate adsorption energies and quite low diffusion barriers of lithium, theoretical storage capacities comparable to Ti2C monolayer, which manifest the double-metal TiNbC and TiNbCO2 monolayers as excellent anode materials for LIBs. [Display omitted] •The lower diffusion barrier of TiNbC displays the best high-rate performance for Li-ion transport.•The TiNbC MXenes exhibits high specific capacity of 351 mAh/g at the OCVs of 0.750 V.•O-groups enhance the open circuit voltage of bare TiNbC for Li-ion, and reduce the storage capacity.•TiNbC and TiNbCO2 are expected for a potential candidate as electrode materials for LIBs.