Comparative study on on lab-scale and continuous industrial sulfur infiltration methods for metal-sulphur batteries

Kurzfassung

In a metal-sulphur battery, the cathode consists of a composite of activated carbon and sulphur, which serves as an electrochemically active material. Both fusion and gas infiltration are used to fill the pores of the activated carbon with sulphur. The overall process with heating and cooling phases is very time and energy intensive. In addition, only very small quantities of sample can be processed in a batch process in the processes established to date. The cost of processing large quantities is so high that the processes are not economically feasible. In order to optimize the production of sulphur-carbon composites, infiltration methods are required that increase the material throughput and improve the duration and energy consumption. To this end, various infiltration methods are used and their performance analyzed. Sulphur is introduced into microporous carbon using various infiltration methods. The methods used are based on both melt and gas infiltration. Continuous industrial processes and rapid batch processes are analyzed and compared with laboratory-scale processes. The investigated methods for sulphur infiltration were carried out with a carbon aerogel, which has a micropore volume of 0.27 to 0.45 cm³/g. The results showed that the highest sulphur loadings could be achieved using gas, extruder and melt infiltrations, with the sulphur predominantly present in the micropores. The composites produced with gas [1] and extruder infiltrations [3] exhibit good cycle stability and high discharge capacity. In comparison, open gas infiltration, microwave infiltration and solvent infiltration showed low sulphur loading and inadequate performance in the cell. The results are summarized in our poster. Our study shows that the following parameters should be taken into account when selecting infiltration methods: - Properties (porosity, pore volume and pore sizes) of the carbon material - Energy, resource and time requirements - Transfer possibilities from laboratory cell to battery production - Battery system (anode material, electrolyte, separator) - Substitution and combination of process steps Depending on the requirements for the battery, the infiltration method can be selected between complex, non-scalable with outstanding performance and economically efficient with moderate performance.