Hierarchical TiO2 spheres assisted with graphene for a high performance lithium-sulfur battery

In this study, we report hierarchical TiO2 sphere-sulfur frameworks assisted with graphene as a cathode material for high performance lithium-sulfur batteries. With this strategy, the volume expansion and aggregation of sulfur nanoparticles can be effectively mitigated, thus enabling high sulfur utilization and improving the specific capacity and cycling stability of the electrode. Modification of the TiO2-S nanocomposites with graphene can trap the polysulfides via chemisorption and increase the electronic connection among various components. The graphene-assisted TiO2-S composite electrodes exhibit high specific capacity of 660 mA h g(-1) at 5C with a capacity loss of only 0.04% per cycle in the prolonged charge-discharge processes at 1C.