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Investigation of Lithium Migration Pathway in Ti2CY2 /Graphene (Y = O, S) van der Waals Heterostructure as Potential Anode Material for Lithium-Ion Batteries: A First-Principle Study
  • Lakshay Girdhar,
  • Paramita Haldar
Lakshay Girdhar
Birla Institute of Technology & Science Pilani - K K Birla Goa Campus
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Paramita Haldar
Birla Institute of Technology & Science Pilani - K K Birla Goa Campus

Corresponding Author:[email protected]

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Abstract

In this work, we have performed first-principle calculations to investigate the electronic properties, structural stability, and lithium migration pathway of 2D Ti 2CY 2/Graphene (Y = O, S) van der Waals (vdW) Heterostructure. The heterostructure formed by O and S functionalized MXene and graphene layers are separated by 3.04 and 3.40 Å exhibiting weak vdW interaction. It is found that the intercalation of lithium (Li) atoms in between the Ti 2CY 2/Graphene layers is thermodynamically more favorable in comparison with intercalation on the top or below the heterostructures. The Bader charge transfer analysis confirms that O atoms gain less charge -0.13 e during Li intercalation compared to S atoms with charge transfer of -0.47 e due to the larger size of the 3p orbital of S atoms. Each Li atom contributes ~0.88-0.89 e during the intercalation process. As O is more negatively charged in comparison with S atoms in the heterostructures, Li atoms are more localized on the Ti 2CO 2 layers with a tendency to form chemical bonds with Ti 2CO 2 layers while they are less localized on the Ti 2CS 2 layers creating lesser chemical bonds. The diffusion energy barrier is lower for Ti 2CS 2/graphene than Ti 2CO 2/graphene during Li intercalation. The NEB study also confirms that the activation energy barrier decreases with the increase of intercalated Li atoms for both the heterostructures indicating that Li atoms exhibit weak repulsive interaction causing weak Li binding with the heterostructures as they increase in number. Both the Ti 2CO 2/graphene and Ti 2CS 2/graphene heterostructures can be considered promising anode materials for Li-ion batteries due to their structural stability, and lower diffusion energy barrier.
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07 Jul 2024Reviewer(s) Assigned
14 Aug 2024Review(s) Completed, Editorial Evaluation Pending
08 Sep 2024Editorial Decision: Revise Major
08 Oct 20241st Revision Received
08 Oct 2024Review(s) Completed, Editorial Evaluation Pending
16 Oct 2024Submission Checks Completed
16 Oct 2024Assigned to Editor