Leaf-Like Graphene-Oxide-Wrapped Sulfur for High-Performance Lithium-Sulfur Battery

Carbon/sulfur composites are attracting extensive attention because of their improved performances for Li-S batteries. However, the achievements are generally based on the low S-content in the composites and the low S-loading on the electrode. Herein, a leaf-like graphene oxide (GO), which includes an inherent carbon nanotube midrib in the GO plane, is synthesized for preparing GO/S composites. Owing to the inherent high conductivity of carbon nanotube midribs and the abundant surface groups of GO for S-immobilization, the composite with an S-content of 60 wt% exhibits ultralong cycling stability over 1000 times with a low capacity decay of 0.033% per cycle and a high rate up to 4C. When the S-content is increased to 75 wt%, the composite still shows a perfect cycling performance over 1000 cycles. Even with the high S-loading of 2.7 mg cm^-2 on the electrode and the high S-content of 85 wt%, it still shows a promising cycling performance over 600 cycles.