Towards high-performance lithium-sulfur battery: Investigation on the capability of metalloid to regulate polysulfides

Lithium sulfur batteries (LSBs) have been a promising rechargeable energy-storage system depending on non-toxicity, low-cost and high theoretical specific capacity. However, the inevitably shuttling of dissolved polysulfides in ether electrolyte and the sluggish redox kinetics still become the obstacles on the way of the commercialization of LSBs. Placing a multifunctional interlayer has been proven a valid method to alleviate the shuttling and boost the conversion of polysulfides. Herein, a germanium (Ge)-doped nitrogen (N)-rich carbon skeleton (GNCS) independent interlayer was proposed through a facile electrospinning technique for LSBs. In this work, Ge nanoparticles, which are embedded in carbon skeleton homogeneously and massively, simultaneously act as catalysts and absorbents for their inherent electronic conductivity and reliable affinity to polysulfides. Meanwhile, the polyacrylonitrile (PAN)-derived nitrogen-rich carbon nanofibers build a threedimensional conductive network for expediting electron transportation of the entire system. The experimental results demonstrate that the LSBs using GNCS interlayers exhibit superior rate performance with the ultrahigh initial capacity of 1680.5 mAh g(-1) at 0.1C, as well as a decent long-cycling performance with high capacity of 755.6 mAh g(-1) after 300 cycling at 1C. This design could not only widen horizons on the usage of metalloids nanoparticles to mediate the activity of polysulfides, but also introduce a facile and practical electrospinning strategy to produce the novel interlayers for realizing the industrialization of LSBs.

Automated summary

This study successfully proposed an independent interlayer made of Ge-doped nitrogen-rich carbon skeleton (GNCS) using electrospinning technique, which can effectively alleviate the shuttle effect in lithium sulfur batteries and boost the conversion of polysulfides. Experimental results demonstrate that LSBs with GNCS interlayers exhibit superior rate performance and decent long-cycling performance.