Carbonaceous multiscale-cellular foams as novel electrodes for stable, efficient lithium–sulfur batteries

Abstract

Porous carbon foams were prepared by pyrolysis of a phenolic resin by a dual template approach using silica monoliths as hard templates and triblock copolymers as soft templating agents. A macroporosity of 50–80% arose from the Si(HIPE) hard template, while the soft template generated micro- or meso-porosity according to the operating procedure. The final materials exhibited a BET specific surface area of 400–900 m² g⁻¹, depending on whether non-ionic surfactants were used during the synthesis; moreover, their performances as Li–sulfide battery positive electrodes were investigated. We determined that the novel 2P5HF carbon foam presents more than 800 mA h g⁻¹ (150 mA h cm⁻³) of remnant capacity after 50 cycles, an unprecedented performance.