Dual Anchoring\nMechanism of Protein-Based Binder for\nLithium–Sulfur Batteries

Abstract

The development of lithium–sulfur (Li–S)\nbatteries\nhas attracted significant attention, but their applications have been\ngreatly hindered by the large volume change of sulfur (S) and the\nshuttle effect of soluble lithium polysulfides (LiPSs). Recently,\nprotein-based binder materials have been introduced on the S cathode\nand have demonstrated great potential in improving the battery performance.\nHere, we systematically investigate the binding mechanisms of LiPSs\nwith different protein side chains through both first-principles density\nfunctional theory calculations and experiments. Our results show that\npeptides with positively charged side chains, such as Arg, have significantly\nhigher binding energies with LiPSs compared to other types of peptides\ndue to a dual anchoring mechanism. The dual anchoring mechanism significantly\nimproved the binding energies of protein-based binders with LiPSs,\nbut it was still within the stability limit. The findings are consistent\nwith our experiments, where adding Arg amino acids into the protein-based\nS cathodes significantly improved the battery performance. The results\nand insights presented in this work will provide guidance on the design\nand optimization of protein-based binders for next-generation Li–S\nbatteries.