Arginine as a Multifunctional Additive for High Performance S-Cathode

Advancement of sulfur (S) cathode of lithium-sulfur (Li-S) batteries is hindered by issues such as insulating nature of sulfur, sluggish redox kinetics, polysulfide dissolution and shuttling. To address these issues, we initiate a study on applying an important amino acid of protein, arginine (Arg), as a functional additive into S cathode. Based on our simulation study, the positively charged Arg facilitates strong interactions with polysulfides. The experimental results indicate that the interaction enable capability of trapping polysulfides within the S cathode, responsible for reducing shuttle effects. Furthermore, the positively charged Arg also promotes efficient ion diffusion and polysulfides conversion. The new findings include that, with addition of only 1 wt % Arg, the resultant cathode demonstrates effectively enhanced electrolyte wettability, polysulfide adsorption and redox kinetics, leading to enhanced rate performance and long-term cycling stability. This study highlights the great potential of amino acids being able to act as effective functional bio-additives in S cathode, paving a new way to high-performance and sustainable energy storage solutions.