Increasing Energy Densities of Sulfur Cathodes using Dispersing and Calendering Processes for Lithium-Sulfur Batteries

摘要

Lithium-sulfur batteries are nearly ready to be commercialized. However, each material composition has specific challenges regarding its adaption to state of the art production lines of lithium-ion batteries. The influence of the dispersing and calendering process on the battery performance is investigated with an easy-to-implement material approach and a solvent-based process. The slurry is treated by different dispersing intensities using an extruder and a triple roller mill, which leads to increased energy densities. The coating is calendered to increase the energy density by maintaining the specific capacity. The reactions within the sulfur cathodes are investigated by evaluating the potentials of the upper and lower voltage plateaus. It was determined that the variation of the process parameters leads to a changed reactivity of the polysulfide reactions but not to a shift of the sulfur utilization within the sulfur cathodes. The process parameters influence the pore structure of the cathode, resulting in different sensitivities for higher C-rates.