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 10vol.% of imidazolium salt into the electrolytes containing lithium salts, the Li–S cells give a greatly enhanced discharge capacity of >600mAhg−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.