Freestanding carbon nanofoam papers with tunable porosity as lithium–sulfur battery cathodes

Abstract

To reach energy density demands greater than 3 mA h cm⁻² for practical applications, the electrode structure of lithium–sulfur batteries must undergo an architectural redesign. Freestanding carbon nanofoam papers derived from resorcinol–formaldehyde aerogels provide a three-dimensional conductive mesoporous network while facilitating electrolyte transport. Vapor-phase sulfur infiltration fully penetrates >100 μm thick electrodes and conformally coats the carbon aerogel surface providing areal capacities up to 4.1 mA h cm⁻² at sulfur loadings of 6.4 mg cm⁻². Electrode performance can be optimized for energy density or power density by tuning sulfur loading, pore size, and electrode thickness.