Highly-flexible 3D Li₂S/graphene cathode for high-performance lithium sulfur batteries

Three-dimensional Li₂S/graphene hierarchical architecture (3DLG) is synthesized with a facile infiltration method. Highly-crystalline Li₂S nanoparticles are deposited homogenously into three-dimensional graphene foam (3DGF) network grown by chemical vapor deposition (CVD), resulting in 3DLG with high surface area, porosity, flexibility and conductivity. The 3DLG is employed as flexible, free-standing and binder-free cathode without metallic current collectors or conducting additives. Due to the unique structure, the 3DLG exhibits a high discharge capacity of 894.7 mAh g⁻¹ at 0.1 C, a high capacity retention of 87.7% after 300 cycles at 0.2 C, and the high-rate capacity up to 4 C reaches 598.6 mAh g⁻¹. The cyclic performance is record-breaking compared to the previous reports on free-standing graphene-Li₂S cathodes. Flexible lithium-sulfur batteries based on the high-capacity 3DLG cathode have promising application potentials in flexible electronics, electrical vehicles, etc.