Self-Supporting Poly (3,4-ethylenedioxythiophene) and Fe3C Co-Decorated Electrospun Carbon Nanofibers as Li2S Supporter for Lithium Sulfur Batteries

Abstract

Lithium Sulfur (Li-S) batteries have attracted great attention in recent years due to their high theoretical energy density (2600 Wh kg-1) and specific capacity (1675 mAh g-1), abundant reserves and environmental friendly. However, the well-known poor electrical conductivity of sulfur/Li2S, shuttle effect of Lithium Polysulfides (LiPSs) and the in-situ formation of lithium dendrites during cycling process extremely hinders the large fabrication of Li-S batteries. In this work, we have designed and prepared a Poly (3,4-ethylenedioxythiophene) (PEDOT) and Fe3C nanoparticles co-decorated Carbon Nanofibers (CNFs) membrane as a self-supporting Li2S host to enhance the electrochemical performance of Li-S batteries. The PEDOT coating layer can tightly connect Fe3C nanoparticles with the CNFs to form a conductive network, which significantly enhancing the conductivity of the cathode. At the same time, the strong chemical adsorption of PEDOT and the catalytic effect of Fe3C can effectively accelerate the conversion kinetics of LiPSs, thereby improving the battery performance. As a result, the optimized PEDOT@CNFs@Fe3C-16wt%/Li2S composite cathode can achieve a high initial specific capacity of 816 mAh g-1 at the current density of 0.1 C. While such cathode also exhibits only 0.033% capacity decay per cycle at 0.5 C after 1000 cycles, showing its advantages as a high-performance self-supporting flexible Li-S composite cathode.