Thirty-minute synthesis of hierarchically ordered sulfur particles enables high-energy, flexible lithium-sulfur batteries

  HaneolKang, MoonJeongPark*  

 An innovative lithium-sulfur (Li-S) battery technology is proposed that provides high energy density, fast charging, and mechanical flexibility. Via the rapid (30 min) one-pot reaction of elemental sulfur and vinyl phosphonic acid (VPA), SVPA microparticles containing dissimilar sulfur allotropes were developed. The spontaneous formation of wrinkles and pores on the particles facilitates electrolyte access and alleviates mechanical stress during battery cycling. The large surface area created by the ordered sulfur domains enhances lithium diffusion coefficients and facilitates polysulfide conversion kinetics in the Li-S cells, leading to a high discharge capacity of 1529 mAh·g⁻¹ at 0.05 C and excellent rate performance (721 mAh·g⁻¹ at 7 C). Additionally, owing to the inherent electrode porosity imparted by SVPA microparticles, a high areal capacity of ~5 mAh·cm⁻² is obtained at increased cathode loadings. Abundant phosphonate moieties at the surfaces and interfaces of particles act as effective chemical anchors for lithium polysulfides, thereby mitigating the shuttle effects, which can prolong cycle lives at various C rates. The impressive properties of the SVPA microparticles are demonstrated for Li-S pouch cells, which exhibit stable operation under various deformations and highlight the SVPA microparticles as a promising candidate for next-generation Li-S batteries for wearable electronics   https://doi.org/10.1016/j.nanoen.2021.106459