Influence mechanism of Nano-Fe₂O₃ on amorphous carbon graphitisation in molecular view via ReaxFF MD simulation

ABSTRACT

Nano-Fe₂O₃/C composites are widely used in the electrochemical energy storage field. Preparing nano-Fe₂O₃/C composites via graphitising the amorphous carbon inserting nano-Fe₂O₃ particles is potential if the influence mechanism of nano-Fe₂O₃ on the graphitisation of amorphous carbon is explored in-depth. Here, an amorphous carbon model (a-C model) and a nano-Fe₂O₃-inserting model (C\Fe₂O₃ model) were built via the liquid-quench method, and the reaction of Fe₂O₃ and C during graphitisation was explored via the reactive force field (ReaxFF) simulation. The results showed that nano-Fe₂O₃ could inhibit the graphitisation of amorphous carbon, and the mechanism was revealed. The Fe₂O₃ molecules collided with the aromatic carbon layer because of the thermal motion, which caused the breaking of the carbon layer and the generation of CO₂ and Fe. Certain Fe reduced from Fe₂O₃ destroyed the aromatic carbon layers by the strong affinity between Fe and C atoms and generated intercalation compounds (FeC_x). Furthermore, the regularisation and stacking of large carbon layers were impeded. Thus, the graphitisation of amorphous carbon was inhibited.

KEYWORDS:

• Disordered carbon
• nano iron oxide
• nano-Fe₂O₃/C composites
• molecular dynamics
• effect mechanism

Acknowledgements

This work was supported by National Natural Science Foundation of China (NO.51904349).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Science Foundation of China: [Grant Number NO.51904349].