Effects of imidazolium salts on discharge performance of rechargeable lithium–sulfur cells containing organic solvent electrolytes

In this study, lithium–sulfur (Li–S) cells using mixed imidazolium salts and lithium salts for the electrolytes are investigated as a means to improve discharge performance and cycle-life characteristics. By introducing 5 or 10 vol.% of imidazolium salt into the electrolytes containing lithium salts, the Li–S cells give a greatly enhanced discharge capacity of >600 mAh g−1 up to the 100th charge–discharge cycle. Furthermore, both the discharge capacity and the average discharge voltage at a high discharge rate, as well as the low-temperature performance, are all dramatically improved when compared with those of conventional cells using organic electrolyte solvents and lithium salts.