Unravelling the anchoring effects of Hd-Graphene for lithium‑sulfur batteries: A first-principles calculation

Abstract

For the widespread commercialization of lithium‑sulfur (LiS) batteries, the identification of anchoring materials capable of effectively mitigating the shuttle effect is of paramount importance. This study is centered around examining the adsorption characteristics of lithium polysulfides (S8 and Li2Sn, n = 1, 2, 4, 6, 8), as well as investigating the sulfur reduction reaction (SRR), and the decomposition mechanisms of Li2S on the pristine and defective Hd-Graphene monolayers. These investigations were carried out using first-principles calculations. The results reveal that the adsorption energies of polysulfides to the electrolytes (DOL and DME) are lower compared to that on the substrates. The moderate anchoring strength (0.8–2.0 eV) between polysulfides and the monolayer can effectively suppress the shuttle effect. Additionally, the Gibbs free energy barrier for SRR on the substrate is determined to be about 0.68 eV. The dissociation energy barrier of Li2S on Hd-Graphene is about 1.54 eV. Lower energy barriers indicate favorable reaction kinetics, leading to improved discharging and charging efficiency. Based on these findings, Hd-Graphene is predicted to be a promising anchoring material for LiS batteries.