Energetics and kinetics of Li intercalation in irradiated graphene scaffolds

TL;DR

This study explores how irradiation-induced defects in graphene scaffolds influence lithium intercalation, revealing that such defects can trap Li atoms but also facilitate diffusion and increase charge capacity, informing battery material design.

Contribution

It provides a detailed analysis of Li intercalation energetics and kinetics near irradiation defects in graphene, highlighting the dual role of defects in trapping and enhancing diffusion.

Findings

Defects create energetically favorable Li adsorption sites.

Defects trap Li atoms but also facilitate interlayer diffusion.

Irradiated graphene can potentially improve Li-ion battery performance.

Abstract

In the present study we investigate the irradiation-defects hybridized graphene scaffold as one potential building material for the anode of Li-ion batteries. Designating the Wigner V22 defect as a representative, we illustrate the interplay of Li atoms with the irradiation-defects in graphene scaffolds. We examine the adsorption energetics and diffusion kinetics of Li in the vicinity of a Wigner V22 defect using density functional theory calculations. The equilibrium Li adsorption sites at the defect are identified and shown to be energetically preferable to the adsorption sites on pristine (bilayer) graphene. Meanwhile the minimum energy paths and corresponding energy barriers for Li migration at the defect are determined and computed. We find that while the defect is shown to exhibit certain trapping effects on Li motions on the graphene surface, it appears to facilitate the interlayer Li diffusion and enhance the charge capacity within its vicinity because of the reduced interlayer spacing and characteristic symmetry associated with the defect. Our results provide critical assessment for the application of irradiated graphene scaffolds in Li-ion batteries.