Fast and facile preparation of S nanoparticles by flash nanoprecipitation for lithium–sulfur batteries

Abstract

This work demonstrates a scalable and continuous flow production of sulfur nanoparticles (SNPs) using a confined impingement jet mixer (CIJ). Sizes and morphology of SNPs can be easily controlled by varying the micro-mixing degree. Using a high feed-speed equal to 110 mL min⁻¹, spherical composites containing SNPs covered with polyvinylpyrrolidone (S@PVP) with uniform morphology and an average diameter of 485 nm were obtained. These composites were tested as active cathode materials for Li–S batteries. Cathodes containing S@PVP composites exhibited high initial capacity equal to 1030.7 mA h g⁻¹. After 50 cycles at C/10, the capacity was 807.7 mA h g⁻¹. Such excellent capacity and capacity retention were attributed to the small size and homogeneous dispersion of SNPs as well as the conducting PVP layer, which provided effective multidimensional electron and ion transport pathways. The PVP layer also mitigated the problems associated with volume expansion, typically occurring during battery cycling. The simplicity and scalability of the method proposed in this work give it very strong potential for large-scale continuous fabrication of SNPs for Li–S rechargeable batteries.