Yolk–Shell\nStructure of Polyaniline-Coated\nSulfur for Lithium–Sulfur Batteries

Abstract

Lithium–sulfur\nbatteries have attracted much attention in recent years due to their\nhigh theoretical capacity of 1672 mAh g^–1 and low\ncost. However, a rapid capacity fade is normally observed,\nattributed mainly to polysulfide dissolution and volume expansion.\nAlthough many strategies have been reported to prolong the cyclability,\nthe high cost and complex preparation processes still hinder their\npractical application. Here, we report the synthesis of a polyaniline–sulfur\nyolk–shell nanocomposite through a heating vulcanization of\na polyaniline–sulfur core–shell structure. We observed\nthat this heating treatment was much more\neffective than chemical leaching to prepare uniform yolk–shell\nstructures. Compared with its sulfur–polyaniline core–shell\ncounterparts, the yolk–shell nanostructures delivered much\nimproved cyclability owing to the presence of internal void space\ninside the polymer shell to accommodate the volume expansion of sulfur\nduring lithiation. The yolk–shell material exhibited a stable\ncapacity of 765 mAh g^–1 at 0.2 C after 200 cycles,\nrepresenting a promising future for industrial scale Li–S batteries.