Recently, MXene/graphene heterostructures have been successfully fabricated and found to exhibit outstanding performance as electrodes for Li ion batteries. However, insights into the mechanism behind the encouraging experimental results are missing. We use first-principles calculations to systematically investigate the electrochemical properties of MXene/graphene heterostructures, choosing Ti2CX2 (X = F, O, and OH) as representative MXenes. Our calculations disclose that the presence of graphene not only avoids restacking effects of MXene layers but also enhances the electric conductivity, Li adsorption strength (while maintaining a high Li mobility), and mechanical stiffness. These favorable attributes collectively lead to the excellent performance of MXene/graphene electrodes observed experimentally. While the Ti2CO2/graphene heterostructure is proposed to be the most promising candidate within the studied materials, the developed comprehensive understanding is of significance also for future rational design of MXene-based electrodes.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This study was financially supported by the National Natural Science Foundation of China (No. 11504303). The authors thank the National Supercomputing Center in Guangzhou for computational resources (Tianhe II supercomputer) and technical support. The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST).