Capturing sulfur: a comparative study on sulfur infiltration techniques of carbon aerogels and novel methods for microstructural analysis

Abstract

Sulfur-infiltrated microporous carbon aerogels are widely used in metal-sulfur batteries or as a capture material for gas-phase mercury adsorption. The present paper deals with two sulfur infiltration techniques and novel characterization methods of sulfur–carbon composites. It is shown that gas-phase as well as microwave-based infiltration techniques are suitable for successful infiltration of microporous aerogels. Nevertheless, some limitations of both methods were identified. Hence, the microstructure, chemical composition, and electrical conductivity of produced samples are comprehensively analyzed. In general, sulfur was found to be partially chemically bonded with carbon, which correlates with the increase of electrical conductivity after gas-phase sulfur infiltration. Furthermore, µ-CT and electron microscopy give a very valuable insight into the structure on macroscopic level. The study provides reliable methods for detailed characterization of sulfur–carbon composites and a better understanding of sulfur infiltration techniques.