A freestanding MoO2‐decorated carbon nanofibers interlayer for rechargeable lithium sulfur battery

Lithium‐sulfur (Li‐S) battery based on sulfur cathodes is of great interest because of high capacity and abundant sulfur source. But the shuttling effect of polysulfides caused by charge‐discharge process results in low sulfur utilization and poor reversibility. Here, we demonstrate a good approach to improve the utility of sulfur and cycle life by synthesizing carbon nanofibers decorated with MoO₂ nanoparticles (MoO₂‐CNFs membrane), which plays a role of multiinterlayer inserting between the separator and the cathode for Li‐S battery. The S/MoO₂‐CNFs/Li battery showed a discharge capacity of 6.93 mAh cm^?2 (1366 mAh g^?1) in the first cycle at a current density of 0.42 mA cm^?2 and 1006 mAh g^?1 over 150 cycles. Moreover, even at the highest current density (8.4 mA cm^?2), the battery achieved 865 mAh g^?1. The stable electrochemical behaviors of the battery has achieved because of the mesoporous and interconnecting structure of MoO₂‐CNFs, proving high effect for ion transfer and electron conductive. Furthermore, this MoO₂‐CNFs interlayer could trap the polysulfides through strong polar surface interaction and increases the utilization of sulfur by confining the redox reaction to the cathode.