Partially Fluorinated Ether as an Electrolyte Additive to Modify Electrode Surface and Suppress Dissolution of Polysulfides in Li-S Batteries

Abstract 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), a kind of fluorinated ether, was used as an electrolyte additive for Li-S batteries. A compact, smooth, and homogenous surface layer was formed on lithium anode at the optimized amount of added TTE. In addition, TTE additive played a crucial role in modifying the composition of the passivation layer on the sulfur/carbon cathode. Consequently, the dissolution and shuttling of polysulfides were effectively prevented. The reversible capacity, initial coulombic efficiency, electrode reaction kinetic, and cycling stability of Li-S batteries were greatly improved.