Lithium–sulfur batteries have attracted much attention in recent years due to their
high theoretical capacity of 1672 mAh g(–1) and low cost. However, a rapid capacity
fade is normally observed, attributed mainly to polysulfide dissolution and volume
expansion. Although many strategies have been reported to prolong the cyclability,
the high cost and complex preparation processes still hinder their practical application.
Here, we report the synthesis of a polyaniline–sulfur yolk–shell nanocomposite through
a heating vulcanization of a polyaniline–sulfur core–shell structure. We observed
that this heating treatment was much more effective than chemical leaching to prepare
uniform yolk–shell structures. Compared with its sulfur–polyaniline core–shell counterparts,
the yolk–shell nanostructures delivered much improved cyclability owing to the presence
of internal void space inside the polymer shell to accommodate the volume expansion
of sulfur during lithiation. The yolk–shell material exhibited a stable capacity of
765 mAh g(–1) at 0.2 C after 200 cycles, representing a promising future for industrial
scale Li–S batteries.