Dual Anchoring Mechanism of Protein-Based Binder for Lithium–Sulfur Batteries

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