Effects of Polysulfide Nonsolvents on the Electrochemical Performance of Li-S Batteries

摘要

The influence of a polysulfide nonsolvent on the electrochemical performance of Li-S batteries wasintensively investigated in two binary DMEonsolvent solutions, namely DME/cyclohexane andDME/toluene, over a range of compositions. The discharge capacities decreased gradually withincreasing nonsolvent content. In particular, Li-S batteries exhibited unusual potential profiles andrapid capacity fading with the binary DMEonsolvent electrolytes of 60% toluene. These featureswere attributed to the phase separation occurring in the electrolytes during the charging anddischarging processes: 1) DME solution containing lithium polysulfides and 2) nonsolvent phase.Incorporating a nonsolvent in an electrolyte solution was not effective in improving the Li-S batteryperformance. In contrast, this study suggests that the application of organic solvents with highpolysulfide solubility and low viscosity are very beneficial in achieving high performance Li-Sbatteries.