Nitrogen-Doped Porous Nanofiber Aerogel-Encapsulated Staphylo-Ni3S2 Accelerating Polysulfide Conversion for Efficient Li–S Batteries

Abstract

The low conductivity of sulfur substances and the fussy effect of lithium polysulfides (LPS) limit the practical application of lithium–sulfur batteries (LSBs). In this work, Ni₃S₂ is in situ synthesized on N-doped 3D carbon nanofibers with an optimized pore structure as a cathode material for LSBs. The conductive carbon nanofiber skeleton with a hierarchical (micropore–mesopore–macropore) structure etched by Cd²⁺ can reduce the interface resistance of the cathode and remiss volume expansion during charge–discharge progress. The Ni was vulcanized and nitrogen-doped successively during the annealing process. In addition, the polar Ni₃S₂ and N-doped carbon structure can promote the catalytic conversion of LPS and regulate the 3D nucleation of Li₂S, which could reduce the reaction energy barrier. Therefore, the NCF-Cd-Ni₃S₂-NC cathode can maintain a high initial capacity (1080.2 mAh g^–1) and excellent stability at 0.1C. This work provides an important basis for the synthesis of high efficiency and inexpensive cathode carrier materials for LSBs.