Thgraphene with High Polysulfide Anchoring Ability\nand Catalytic Performance for Advanced Na–S Batteries: A First-Principles\nStudy

The\nsodium–sulfur (Na–S) batteries, with advantages\nsuch as high energy density, high specific capacity, and low cost,\nhave attracted significant attention in the field of rechargeable\nbatteries in recent years. However, their practical application still\nfaces many challenges. In this study, we employ first-principles calculations\nto investigate the performance of a 2D carbon allotrope, thgraphene,\nas an anchoring material in Na–S batteries. Our studies reveal\nthat thgraphene possesses the modest adsorption strength (0.70–1.75\neV) toward S<sub>8</sub>/Na<sub>2</sub>S<sub><i>n</i></sub> species, which is beneficial for inhibiting the dissolution and\nshuttle effect of sodium polysulfides. Furthermore, thgraphene demonstrates\nexcellent bifunctional catalytic activity, displaying reduced Gibbs\nfree energy barrier (0.58 eV) for sulfur reduction reaction (SRR)\nand lower Na<sub>2</sub>S decomposition barrier (0.76 eV); thus, it\nwould greatly enhance the electrode reaction kinetics during the charge/discharge\nprocesses. Additionally, we find that applying certain strain can\nnot only maintain the adsorption strength of S<sub>8</sub>/Na<sub>2</sub>S<sub><i>n</i></sub> species but also improve the\nsulfur reaction activity. These theoretical findings provide an avenue\nfor the potential application of thgraphene in Na–S batteries.