Arginine as an Effective Electrolyte Additive for Dual-Interface Stabilization in Li–S Batteries

Lithium–sulfur (Li–S) batteries are touted for their attractive theoretical performance specifications, which greatly surpass the limits of conventional lithium-ion batteries. However, their commercialization is halted by Li dendrite growth and the notorious polysulfide shuttle effect. In this study, we apply a positively charged amino acid, l-arginine (Arg), as an effective electrolyte additive for stabilizing both electrodes simultaneously. The additive combats the shuttle effect by forming a solid precipitate with polysulfide intermediates, while also suppressing Li dendrite growth via electrostatic shielding. As a result, symmetrical Li||Li cells equipped with the additive display extended lifespans (>500 h, vs ∼205 h with the blank electrolyte). More notably, Li–S cells benefit from both mechanisms, displaying improvements in capacity retention (65% vs 51% for the blank electrolyte, after 300 cycles at 0.2 A/g). This study introduces Arg as an effective dual-interface stabilizer for both the Li anode and the S cathode, highlighting amino acids as promising biomolecules for sustainable energy storage.