Improved Low-Temperature Performance of Li-S Batteries via “Solid-Solid” Conversion of Sulfur

Lithium-sulfur (Li-S) batteries under the traditional “solid-liquid-solid” cathode process experience serious capacity degradation at low temperatures, because the intermediate polysulfides which dissolved into the electrolyte tend to cluster. Herein, a “solid-solid” conversion of sulfur is realized via an in situ formed protective layer on the cathode surface which separates the sulfur species from the electrolyte. So that the dissolution and agglomeration problem of the polysulfides is suppressed. As a result, the sulfur cathode via “solid-solid” conversion demonstrates a significantly improved low-temperature performance, even under lean electrolyte condition. This work provides a promising direction for developing available Li-S batteries under cryogenic conditions.