Role of ionic liquids as electrolyte additives in enhancing the electrochemical performances of Lithium Sulfur Batteries

The lithium-sulfur batteries (Li-S) found an unprecedented advantage in the post-lithium era owing to their exceptional discharge capacity, low cost, and environmental friendliness, thereby reducing greenhouse gas emission to 31%. Unfortunately, the commercialization of this unique system is still undermined owing to the poor conductivity of elemental sulfur, shuttling of lithium polysulfide, and more importantly, the self-discharge of lithium sulfur batteries. The shuttle effect of LiPS leads to the loss of active sulfur in the cathode and undesirable interactions with the Li metal anodes, leveraging the overall performance of lithium sulfur batteries. Besides, the corrosion of current collectors also exacerbates the self-discharge of lithium sulfur batteries. Numerous approaches have been introduced to mitigate these challenges in Li-S batteries. Among them, introduction of electrolyte additives has been identified as a potential tool to improve the discharge capacity and Columbic efficiency of Li-S batteries. In the present work, a combination of ionic liquids and lithium salt has been introduced in the conventional non-aqueous liquid electrolytes, and their charge-discharge and electrode/electrolyte interfacial properties were extensively examined. These simultaneous changes at the cathode and anode synergistically accelerate the overall performance of Li-S batteries.