Magnetic and mesoporous Fe3O4-modified glass fiber separator for high-performance lithium-sulfur battery

Lithium-sulfur batteries are attractive for energy storage due to their ultrahigh theoretical energy density and low material cost. But the biggest factor impeding the development of the batteries is its rapid irreversible capacity decay due to the “shuttle effect.” To inhibit it, the glass fiber membrane modified by magnetic mesoporous Fe 3 O 4 mixed with Ketjen black is designed and used as the separator for lithium-sulfur batteries in this work. The assembled battery using the modified separator exhibits an excellent initial capacity of 1274.5 mA h g −1 and a high coulombic efficiency of about 90% at 0.2 C first cycle. The improved performance of batteries can be ascribed to the good conductivity, mesoporosity, and magnetic property of Fe 3 O 4 nanoparticles on the separator, which enables the trapping and activation of the soluble polysulfides in lithium-sulfur batteries. The work indicates that magnetic mesoporous Fe 3 O 4 can open new avenues to improve the performance of lithium-sulfur batteries.