Metal-organic framework-based glass fiber separator as an efficacious polysulfide barrier and dendrite suppressor for lithium-sulfur batteries

The polysulfide shuttle and uncontrollable growth of lithium dendrites are the two fatal troubles that obstruct the practical process of lithium-sulfur batteries. Herein, a composite membrane consisting of metal-organic framework (MOF) Ce-based UiO-67 and glass fiber membrane (UiO-67-GF) is proposed as a dual-functional separator for these issues. On the one hand, the introduced Ce-UiO-67 crystals are capable of efficaciously adsorbing polysulfides and catalyzing their conversion, thereby restraining their shuttle. On the other hand, this MOF provides sufficient lithium-philic functional groups for ensuring the rapid and homogeneous transport of Li ions , and thus a stable Li plating and stripping process can be acquired. Consequently, this MOF-based separator is qualified for simultaneously resolving the challenges of polysulfide shuttle and Li dendrite. The battery with the proposed separator delivers an initial capacity of 919 mAh g −1 and a limited decay rate of merely 0.04% per cycle for 500 cycles at 1 C. Moreover, even under a lean-electrolyte condition, a high area capacity of 6.0 mAh cm −2 is still obtained under the increased sulfur loading of 7.0 mg cm −2 .