Tow-dimensional metal organic framework decorated porous carbon fiber as efficient interlayer for lithium-sulfur battery

• •A double cross-linked structure is constructed with ZIF-7@PCF as interlayer. • •The porous PCF provides good electrical conductivity and efficient Li + diffusion. • •The layered ZIF-7 offers multiple active sites for LiPS trapping and redox reaction. • •The unique double cross-linked structure can improve the structural stability. In order to address the shuttling effect of lithium polysulfide (LiPS) in lithium-sulfur (Li-S) batteries, an efficient interlayer composite was fabricated by growing tow-dimensional metal organic framework (MOF) on porous carbon nanofiber (PCF). The interlayer has a double cross-linked structure formed by ZIF-7 nanosheets MOF and PCF fibers (ZIF-7@PCF). The PCF was obtained by heat treatment of polymer fibers prepared by electro-spinning technique. The PCF possesses a conductive porous carbonaceous skeleton, which can promote the electron and ion transportation in the cell. Meanwhile, the ZIF-7 MOF offers abundant active sites for LiPS trapping and conversion reaction. This unique double cross-linked structure design endows the ZIF-7@PCF interlayer with excellent performance in mitigating LiPS shuttling in the cell. As a result, the Li-S battery with the ZIF-7@PCF interlayer delivers an initial discharge specific capacity of 1221 mAh g −1 at of 0.2C and a good rate performance with a specific capacity of 661.3 mAh g −1 at 5C. Even under long-term cycling test at 1C, a benign cycling performance can be achieved with a discharge specific capacity of 812 mAh g −1 after 500 cycles, corresponding to a capacity decay rate of 0.03% per cycle.