Superior Performance of a Lithium-Sulfur Battery Enabled by a Dimethyl Trisulfide Containing Electrolyte

The lithium-sulfur (Li-S) battery offers a high theoretical energy density of approximate to 2600 Wh kg(-1) and low cost, positioning it as a promising candidate for next-generation battery technology. However, problems including disastrous Li polysulfides dissolution and irreversible Li2S deposition have severely retarded the development of Li-S batteries. To solve these issues, a functional dimethyl disulfide (DMDS)-containing electrolyte was recently reported that promotes an alternate electrochemical reaction pathway for sulfur cathodes by the formation of dimethyl polysulfides and Li organosulfides as intermediates and reduction products, leading to significantly boosted Li-S cell capacity with improved cycling reversibility and stability. Here, dimethyl trisulfide (DMTS), a primary discharge-charge intermediate in the DMDS-containing electrolyte, which is also a commercially available reagent, is further investigated as a cosolvent in functional electrolytes for Li-S batteries. Due to the higher theoretical capacity of DMTS and its better reactivity with Li2S than DMDS, a 25 vol% DMTS-containing electrolyte enables Li-S batteries with even higher cell capacity and improved cycling performance than using previous optimal 50 vol% DMDS-containing electrolyte.