Modelling and characterization of carbon networks

Abstract

Carbon aerogels are highly open-porous solid materials in which a gas occupies more than 90% of their volume. Therefore, they show a low density, a large inner surface area, a high pore volume and high electrical conductivity. These properties make carbon aerogels an excellent candidate for a cathode material for metal-sulphur batteries. The conversion reaction of sulphur and the formation of Li2S cause a large volume expansion, which results in a reduction of electron transport paths and thus a decrease in kinetics. Flexible carbon aerogels with tailored microstructure can accommodate volume expansion due to their ability for reversible deformation up to a certain degree during cycling, thereby resulting in high-performance cells. In this work, we present first experimental results on the synthesis and characterization of stiff and flexible carbon aerogels. Carbon aerogels are synthesized by carbonization of resorcinol-formaldehyde aerogels produced by sol-gel process. Density, pore size and inner surface area of these aerogels are measured to study their potential applications in metal-sulphur batteries. First look into the methodology and results on a first-of-its-kind molecular study on a stiff carbon aerogel-like nanostructures will also be presented. Molecular dynamics (MD) studies present a detailed insight into the atomic-scale phenomena that underlie the formation of the porous network of carbon aerogels. The AIREBO potential3, which is shown to accurately interpret carbon-carbon interactions, is used to simulate the nano-porous carbon network. The mechanical properties of these initial carbon networks are studied under uniaxial compression.