Three-Dimensional Carbon Networks Decorated with Co Nanocatalysts as Multifunctional Interlayers for a High-Performance Lithium–Sulfur Battery

The notorious shuttle effect and slow redox kinetics have hindered the practical application of lithium–sulfur batteries (LSBs). To address these issues, a three-dimensional carbon network decorated with highly active nanocatalyst design is proposed as a multifunctional interlayer in LSBs. In this design strategy, reduced graphite oxide (rGO) is infiltrated into the internal skeleton of the carbon fiber (CF) film. This forms a dense rGO-CF carbon substrate on which in-situ catalytic growth of carbon nanotubes (CNTs) is introduced, leading to the formation of an interlayer decorated with Co nanocatalysts. The resulting Co/CNT@rGO-CF interlayer acts as a physical barrier, inhibiting the shuttling of lithium polysulfides (LiPS). In addition, CNTs are decorated with abundant Co nanoparticles, forming highly active catalytic tentacles towards promoted LiPS trapping and conversion. As a result, the cell with Co/CNT@rGO-CF interlayer achieves a high capacity of 821.7 mA h g –1 after 500 cycles at 1 C with a capacity decay of 0.029% per cycle. At a high current density of 5 C, a capacity of 700.6 mA h g –1 is also obtained. Furthermore, even at the high sulfur loading of 6.7 mg cm –2, the cell still has an excellent capacity performance of 5.23 mA h cm –1 . This design of this unique interlayer structure is of great significance to suppress the shuttle effect of LiPS.