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.