Yolk–shell structured sulfur composite cathode for high performance lithium–sulfur battery

Abstract

Lithium-sulfur batteries (LSBs) are suffered from the unavoidable “shuttle effects” of lithium polysulfides (LPS) and the infinite volume change of the sulfur. Herein, we prepared a yolk-shell structured N-doped carbon nanotubes/sulfur/poly(3,4-ethylenedioxythiophene) nanotubes (N-CNTs/S@PEDOT) composite as cathode for LSBs. The yolk-shell structure with void spaces can effectively buffer the volume expansion of sulfur, while the outer “shell” can act as a physical barrier to minimize the “shuttle effects” of LPS. Moreover, the N-CNTs with high conductivity and superior structural stability are able to improve the electron transfer efficiency and cycling performance. Therefore, the specially designed yolk-shell structured N-CNTs/S@PEDOT composite cathode exhibits an extraordinary rate performance and enhanced cycling stability (602 mAh g⁻¹ after 200 cycles at 0.1 C).