Carbon-based cathode host derived from crosslinked porous polyimides for lithium-sulfur batteries and their electrochemical properties

Abstract

Carbon-based porous materials as Li–S batteries cathode hosts have received widespread attention because of the superiority of fine physical confinement, vast accommodation voids and excellent conductive networks, towards realizing the adsorption-diffusion-conversion of lithium polysulfides (LiPSs). However, carbon-based materials are usually non-polar, which can only act as physical barriers to limit polysulfides shuttle behavior during short-term cycling of Li–S batteries, lacking strong chemical entrapment towards the polar polysulfides. Herein, we successfully synthesize two novel carbon-based hierarchical porous materials (CR-PPIs@800) derived from crosslinked porous polyimides (CR-PPIs) via traditional polymerization and crosslinking reaction as well as high-temperature treatment. Because the pre-designed porous architectures, CR-PPIs@800 not only give hierarchical porous structure for accommodating LiPSs, but also afford strong chemisorption interaction from high heteroatom N species for adsorbing LiPSs and buffering shuttle behaviors. The carbon networks of CR-PPIs@800 possess valid ion storage and transportation network for accelerating charge/ion migration of LiPSs. Profiting from above advantages, S/CR-PPIs@800 composites cathodes realize the fast conversion of LiPSs, and show promoted electrochemical properties.