Analysis of the reactions of electrolyte and cathode in lithium/sulfur and lithium metal sulfide batteries, AReLiS. Subproject: Analysis of the cathode-electrolyte interface in Li/sulfur and Li/metal sulfide batteries. Final report

The aim of the AReLiS project in general was to deepen the understanding of the conversion reactions in lithium/sulfur (Li/S) and lithium/metal sulfide (Li/$M_x{S}_y$) batteries and to expand them compared to the state of the art. The focus here was on the interaction of the electrolyte with the cathode. A major challenge of the sub-project at TU Dresden was to suppress the formation of polysulfides dissolved in the electrolyte by encapsulated sulfur species and metal sulfides in combination with organic carbonate electrolytes. Initially, the cathode system made of sulfur-conductive carbon black with an ether-based electrolyte served as a reference system. This was compared with composites made of sulfur and microporous carbon as well as amorphous metal sulfides. The respective morphology and structure of the materials were varied based on the synthesis parameters. The aim was to specifically adjust the pore geometry, the specific surface area and the pore volume of the carbons. Metal sulfides with different particle morphologies and compositions were also produced by the partner AIST in Osaka, sent to the TU Dresden and evaluated morphologically and electrochemically. The cathode active material was to be processed into a cathode using a dry film process. The ether-containing electrolyte was replaced by carbonate-based electrolytes. The overarching goal was to develop Li/S battery cathodes and associated electrolytes with adapted cycling conditions that would potentially achieve high energy densities at prototype cell level.