Facile one-pot synthesis of well-defined coaxial sulfur/polypyrrole tubular nanocomposites as cathodes for long-cycling lithium–sulfur batteries

Abstract

Well-defined core–shell structured coaxial sulfur/polypyrrole tubular nanocomposites, polypyrrole nanotubes wrapped by uniform rough sulfur layers, were fabricated as Li–S battery cathodes via a facile one-pot method. In the designed structure, the polypyrrole backbone can facilitate the charge transport and also restrain the soluble polysulfide diffusion, while the active sulfur layer can efficiently react with Li⁺ assisted by the PPy nanotubes, and the lithium polysulfides can be massively trapped by the PPy nanotubes during charge–discharge processes. The as-prepared coaxial sulfur/polypyrrole tubular nanocomposites with a sulfur loading of 53.3% exhibited a high initial discharge specific capacity of 1117 mA h g⁻¹ with a remarkable cycling stability, retaining 692 mA h g⁻¹ and 525 mA h g⁻¹ after 200 cycles at a current density of 0.2C and 1C, respectively. Moreover, they expressed an excellent rate capability performance, maintaining 470 mA h g⁻¹ at a high current density of 2C.