The importance of the dissolution of polysulfides in lithium-sulfur batteries and a perspective on high-energy electrolyte/cathode design

The dissolution of polysulfides is widely considered to be a major obstacle for developing lithium-sulfur batteries (LSBs) because it results in a shuttle effect. A popular strategy to address this issue is preventing polysulfide dissolution, e.g., trapping/confining polysulfides in porous carbons. However, this conflicts with the advantage of commonly used ether-based electrolytes, i.e., the dissolution of polysulfides in such electrolytes is beneficial for delivering Li+ to sulfur-based species compared to sluggish solid-state transport. Thus, a question is raised on the feasibility of the strategy to prevent polysulfide dissolution. Here, it is shown that the dissolution of polysulfides in ether-based electrolytes is necessary for a high capacity, suggesting that it might not be right to prevent the dissolution of polysulfides in such electrolytes. Thus, other approaches should be developed. A perspective is hence provided for designing electrolyte/cathode for high-energy LSBs.Ministry of Education (MOE)National Research Foundation (NRF)Submitted/Accepted versionThis research was supported by the National Research Foundation, Prime Minister’s Office, Singapore, under its Campus for Research Excellence and Technological Enterprise (CREATE) program. The work was partially supported by the Singapore Ministry of Education Tier 1 grant (2019-T1-002- 125)