First–principles study of potassium adsorption and diffusion on graphene

Abstract

Potassium–ion batteries (KIBs) are a new–type of energy storage devices that have attracted increasing attention due to their low cost and the abundant resource of K in the Earth’s crust. Monolayer and multilayer graphene are promising electrode materials for KIBs. Herein, the adsorption and diffusion of potassium atoms on the surface of graphene were studied using the first–principles calculations including the van der Waals interaction. It was determined that K atoms can stably adsorb on the surface of graphene. The climbing image nudged elastic band method was employed to calculate the diffusion barriers of a single K atom and two K atoms on the surface of graphene. The results demonstrated that the diffusion barrier of a single K atom on graphene was low. The interaction between K atoms was considered and it facilitates the K atom diffusion to the second and third nearest–neighbour site of the K adatom, but prevents the K atom diffusion to the far nearest–neighbour site of the K adatom. Moreover, the difference in charge density demonstrates that there was a significant charge transfer from two K adatoms to its nearest–neighbour carbon atoms.

GRAPHICAL ABSTRACT

KEYWORDS:

• Graphene
• potassium
• first–principles calculations
• potassium–ion batteries

Acknowledgements

We gratefully acknowledge Prof. Bo Song for helpful discussions. This work was supported by the Shanghai Supercomputer Center of China, and the Shangdong Computer Science Center of China.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

National Natural Science Foundation of China [grant number 11447152], [grant number 11447176] [grant number 11547239]; Academic Discipline Project of Shanghai Dianji University [grant number 16JCXK02]; Plateau Disciplines in Shanghai [grant number 18GYXK01].