Herein we report a simple approach for the preparation of graphene oxide-carbon nanotube-sulfur composites. The self-standing composites can be easily prepared by freeze drying a frozen graphene oxide-carbon nanotube suspension, and then impregnated with sulfur by melt diffusion. Composites obtained in this way are physicochemically characterized by elemental analysis, X-ray diffractometry (XRD), electron microscopy and gas adsorption, showing a three dimensional macroporous graphene-based architecture in which sulfur is homogeneously distributed. The performance of self-standing composites with sulfur loadings over 4.0 mg cm⁻² is evaluated as binder-free positive electrodes for Lithium-Sulfur (Li-S) batteries. Results show that the incorporation of just 2 wt.% of CNTs significantly improves both the specific capacity and capacity retention compared to the results shown by the CNT-free samples, and slightly improves the performance of thermally reduced samples. More importantly, reversible specific capacity values over 500 mAh g⁻¹ at a rate of 0.1C after 100 charge/discharge cycles are obtained for either thermally reduced and CNT containing samples, which in terms of areal capacity correspond to values over 2.0 mAh cm⁻².

在这里，我们报告了一种简单的方法来制备氧化石墨烯-碳纳米管-硫复合材料。通过冷冻干燥冷冻的氧化石墨烯-碳纳米管悬浮液，然后通过熔融扩散将硫浸渍，可以容易地制备自立复合材料。通过元素分析，X射线衍射（XRD），电子显微镜和气体吸附对以这种方式获得的复合材料进行物理化学表征，显示出三维大孔石墨烯基结构，其中硫均匀分布。硫负载量超过4.0 mg cm ^-2的自立复合材料的性能被评估为锂硫（Li-S）电池的无粘合剂正极。结果表明，与不含CNT的样品显示的结果相比，仅掺入2 wt％的CNT显着提高了比容量和容量保持率，并且略微提高了热还原样品的性能。更重要的是，超过500毫安克可逆比容量值^-1在0.1C的后100次充电/分的速度被用于任一热还原和含CNT的样品，获得放电循环，其在超过2.0毫安厘米面积容量对应的条款值^{- 2}。