Assessing Ni₂(dobpdc) Anchoring for Mitigating Lithium Polysulfide Dissolution in Lithium–Sulfur Batteries

In this work, we have explored sulfur loading, the anchoring ability of lithium polysulfides (LiPSs), and the formation mechanism of a net-like Li2S structure in a Ni2(dobpdc) metal–organic framework (MOF) using density functional theory (DFT) calculations and molecular dynamics (MD) simulations. The MD results reveal a net-like structure of (Li2S)n covering the Ni2(dobpdc) MOF surface when the S8 cluster is transformed into short-chain LiPS molecules at a high level of lithiation. Further, the LiPS molecules adsorbed on the Ni2(dobpdc) MOF surface (in the presence of a solvent) have been considered. Based on the electron distribution analysis of the three-dimensional reference interaction site model (3D-RISM) results, 1,3-dioxolane (DOL) can hinder LiPS dissolution owing to its weak binding strength with the LiPS molecules. In contrast, the ethylene carbonate (EC) solvent significantly decreases the adsorption strength of the long-chain LiPS molecules, leading to a severe shuttling effect of the LiPSs in Ni2(dobpdc). Our findings indicate that the shuttling effect of the LiPSs is highly dependent on the dielectric constant of solvents, suggesting that solvents with a strong polarizability, such as EC, should be avoided. The present findings also offer comprehensive insights into the impact of various solvents on LiPS adsorption in Ni2(dobpdc), paving the way for developing innovative cathode materials for next-generation Li–S batteries.