One-Pot Synthesis of Functionalized Holey Graphene/Sulfur Composite for Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are promising energy storage devices owing to their high theoretical energy density and environmental friendliness. However, drawbacks such as poor conductivity of element sulfur, shuttle effect, and serious volume expansion hinder the application of Li-S batteries. Herein, this paper reports a functionalized holey graphene/sulfur composite fabricated by a facile one-pot synthesis method as the cathode for Li-S batteries. The uniformly and densely distributed microholes are etched out on graphene sheets by H2O2 oxidation, with the tunable hole- size and the oxygen-functional group doping along the hole-edge. The numerous microholes serve as the fast pathways for ions through the graphene sheets, while the polar oxygen-functional groups inhibit the movement of lithium polysulfides. Such a functionalized holey graphene/sulfur composite with the optimal hole-size of 0.6 nm shows a significantly enhanced electrochemical performance compared with the control sample without the microholes or functional groups.