Tuning Na-Ion Diffusion in MXene/Graphene Oxide Heterostructures: An Ab Initio Molecular Dynamics Study

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Sodium-ion batteries (SIBs) are a promising alternative to lithium-ion batteries.
• Developing high-performance anode materials is critical for advancing SIB technology.
• Heterostructured materials offer unique properties for improved electrochemical performance.

Purpose of the Study:

• To investigate the impact of graphene oxide oxidation on sodium-ion (Na-ion) intercalation and diffusion in MXene/graphene oxide heterostructures.
• To understand the atomic-scale mechanisms governing Na-ion transport within these heterostructures.
• To determine the optimal oxidation degree of graphene oxide for enhanced SIB anode performance.

Main Methods:

• Ab initio molecular dynamics simulations.
• First-principles calculations.
• Atomic-scale analysis of ion diffusion and structural properties.

Main Results:

• Graphene oxide functional groups increase interlayer spacing, facilitating initial Na-ion embedding.
• Overoxidation of graphene oxide hinders Na-ion diffusion pathways.
• An optimal oxidation level balances Na-ion kinetics and structural integrity for efficient migration.

Conclusions:

• Rational design of MXene/graphene oxide heterostructures requires careful control of graphene oxidation.
• Optimized heterostructures exhibit excellent capacity and cycling stability for SIB anodes.
• This study provides fundamental insights for developing advanced MXene-based anode materials for SIBs.