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

In order to address the shuffling 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 conducive 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.

Automated summary

By growing ZIF-7 nanosheets MOF on PCF, researchers successfully fabricated an efficient interlayer composite with a double cross-linked structure, which can effectively mitigate the shuffling effect of LiPS in lithium-sulfur batteries. The unique design of ZIF-7@PCF interlayer demonstrates excellent performance in high-rate and long-term cycling tests for lithium-sulfur batteries.