Modification of Polyethylene Separators Based on Graphene Oxide in Lithium-Sulfur Batteries

Graphene oxide (GO) coated polyethylene (PE) separator was successfully prepared by a quadruple film applicator and the effect of the oxidation degree of GO on performances of lithium-sulfur batteries was studied. The structures of GO were characterized by XPS. The properties of GO coated separator were investigated by SEM, A.C. impedance, polysulfide permeability test and charge-discharge experiments. Results revealed that GO coated separator could prohibit the "shuttle effect" of lithium-sulfur batteries. Moreover, it was found that the battery assembled with the GO-4 coated separator showed the best cycle performance, because GO-4 had high electrical and high oxidation degree. The initial specific discharge capacity of lithium-sulfur batteries using the GO-4 coated separator was 900.0 mA·h/g, higher than that of PE separator (763.2 mA·h/g).