Self-supporting poly(3,4-ethylenedioxythiophene) and Fe3C Co-decorated electrospun carbon nanofibers as Li2S supporters for lithium–sulfur batteries

Abstract

Lithium–sulfur (Li–S) batteries have attracted significant attention in recent years owing to their high theoretical energy density (2600 W h kg⁻¹) and specific capacity (1675 mA h g⁻¹), abundant reserves and environmental friendliness. However, the well-known poor electrical conductivity of sulfur/Li₂S, shuttle effect of lithium polysulfides (LiPSs) and in situ formation of lithium dendrites during the cycling process extremely hinder the large-scale application of Li–S batteries. In this work, we designed and prepared poly(3,4-ethylenedioxythiophene) (PEDOT) and Fe₃C nanoparticle co-decorated carbon nanofiber (CNF) membranes as self-supporting Li₂S hosts to improve the electrochemical performance of Li–S batteries. The PEDOT coating layer firmly connected the Fe₃C nanoparticles with the CNFs to form a conductive network, significantly enhancing the conductivity of the cathode. Simultaneously, the strong chemical adsorption of PEDOT and the catalytic effect of Fe₃C effectively accelerated the conversion kinetics of LiPSs, thereby improving the battery performance. As a result, the optimized PEDOT@CNFs@Fe₃C-16wt%/Li₂S composite cathode achieved a high initial specific capacity of 816 mA h g⁻¹ at a current density of 0.1 C. Furthermore, the cathode exhibited only 0.033% capacity decay per cycle at 0.5 C after 1000 cycles, showing its potential as a high-performance self-supporting flexible Li–S composite cathode.