An Efficient Separator with Low Li-Ion Diffusion Energy Barrier Resolving Feeble Conductivity for Practical Lithium-Sulfur Batteries

Due to unprecedented features including high-energy density, low cost, and light weight, lithium-sulfur batteries have been proposed as a promising successor of lithium-ion batteries. However, unresolved detrimental low Li-ion transport rates in traditional carbon materials lead to large energy barrier in high sulfur loading batteries, which prevents the lithium-sulfur batteries from commercialization. In this report, to overcome the challenge of increasing both the cycling stability and areal capacity, a metallic oxide composite (NiCo2O4@rGO) is designed to enable a robust separator with low energy barrier for Li-ion diffusion and simultaneously provide abundant active sites for the catalytic conversion of the polar polysulfides. With a high sulfur-loading of 6 mg cm(-2) and low sulfur/electrolyte ratio of 10, the assembled batteries deliver an initial capacity of 5.04 mAh cm(-2) as well as capacity retention of 92% after 400 cycles. The metallic oxide composite NiCo2O4@rGO/PP separator with low Li-ion diffusion energy barrier opens up the opportunity for lithium-sulfur batteries to achieve long-cycle, cost-effective operation toward wide applications in electric vehicles and electronic devices.