Controlled synthesis of porous carbon nanostructures with tunable closed mesopores via a silica-assisted coassembly strategy

Abstract

Controllable fabrication of mesoporous carbon nanoparticles (MCNs) with tunable pore structures is of great interest, due to the remarkable effect of pore structure on electrochemical performance of the materials. However, it has remained a major challenge. Here, we demonstrate the controlled synthesis of MCNs with tunable closed pore structures via a silica-assisted coassembly strategy, which employs polystyrene-block-poly(ethylene oxide) diblock copolymers as soft template, phenolic resol and tetraethyl orthosilicate as carbon and silica precursors, respectively. Through simply varying the sequential cross-linking of the silica and carbon precursors or the copolymer composition, novel MCNs with alluring spherical, hollow-hoop-structured, or yolk-shell-like closed mesopores are tunably prepared. In particular, serving as cathode materials of lithium-sulfur batteries, the resultant silica-hybridized MCNs with the exceptional hollow-hoop mesopores and a moderate sulfur-loading content of 46 wt % exhibit top-level electrochemical performance. This study opens an avenue for tunable construction of mesoporous particles with closed pores and provides clues for the effect of pore geometry on the electrochemical performance of porous cathode materials for lithium-sulfur batteries.