A theoretical study of 2D polymeric C24 networks as high-performance anchoring materials for lithium–sulfur batteries

Abstract

Lithium–sulfur batteries are seen as promising next-generation energy storage systems, offering numerous advantages; however, their large-scale commercialization encounters many challenges. This study employs first-principles calculations and ab initio molecular dynamics (AIMD) simulations to evaluate the potential of recently reported two-dimensional (2D) polymeric C₂₄ networks as anchoring materials for lithium–sulfur (Li–S) batteries. Both quasi-hexagonal phase (qHP) and quasi-tetragonal phase (qTP) C₂₄ monolayers and bilayers demonstrate kinetic and thermodynamic stability along with semiconductor characteristics. C₂₄ bilayers show a significantly stronger affinity for S₈ and lithium polysulfides (LiPSs), particularly long-chain species, effectively suppressing dissolution and the shuttle effect. This high affinity is supported by charge transfer assessments and large positive values of the integrated crystal orbital overlap population (COOP). A strong linear correlation between adsorption energies and COOP values establishes COOP as an effective bonding descriptor. Both C₂₄ monolayers and bilayers demonstrate effective catalytic performance during the sulfur reduction reaction (SRR). Notably, C₂₄ bilayers show superior catalytic activity for the decomposition of Li₂S. The adsorption of S₈ and LiPSs within C₂₄ bilayers does not result in significant volume expansion. The C₂₄ networks, in particular the bilayers, demonstrate exceptional anchoring and catalytic performance, offering promising potential for high-performance Li–S batteries.