Free-standing porous carbon nanofibers–sulfur composite for flexible Li–S battery cathode

Abstract

Flexible and free-standing sulphur/(PCNFs–CNT) composite (S@PCNFs–CNT) electrode was successfully prepared by infiltrating sulfur into microporous carbon nanofibers–carbon nanotube (PCNFs–CNT) composite. When used as a cathode material for Li–S batteries, the S@PCNFs–CNT exhibits much better cycle performance and rate performance compared to CNT-free S@PCNFs. It delivers a reversible capacity of 637 mA h g⁻¹ after 100 cycles at 50 mA g⁻¹ and a rate capability of 437 mA h g⁻¹ at 1 A g⁻¹. The improved electrochemical performance is attributed to synergistic effect of the 3D interconnected structure, the additive of CNT, and the uniform distribution of micropores (<2 nm) in the PCNFs–CNT matrix. Our results indicate the potential suitability of PCNFs–CNT for efficient, free-standing, and high-performance batteries.