Capturing Sulfur in Micropores: Novel methods for investigating sulfur deposition in highly-porous carbon aerogels

Kurzfassung

Sulfur-infiltrated carbon aerogels have attracted a great attention in recent decades. Carbon aerogels and their organic precursors represent a large and important class of aerogels. Their porosity, pore sizes and volume, as well as inner surface area can be tailored for different kinds of application, such as electrode materials, adsorbers for hydrogen storage or catalyst support. The micropores are crucial especially for application fields such as metal-sulfur batteries or as a capture material for gas-phase mercury adsorption. Moreover, slow and controlled release of fertilizers or fungicides can be achieved with sulfur-containing materials. The micropores here act as cages that prevent the sulfur from escaping easily and provide sufficient volume for it. The poster presents two sulfur infiltration techniques and novel characterization methods of sulfur-carbon composites. For this work two highly microporous carbon aerogels were developed. 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 is 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 beneficial 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.