Interplay of Binder and Mixing Duration Effects on Lithium–Sulfur Battery Slurry and Electrode Properties

In our quest to optimize the sulfur particle size distribution with minimal material loss during slurry preparation for lithium–sulfur (Li–S) batteries, we applied the simple and effective method of simultaneously mixing and milling the slurry components in a ‘one‐pot’ process. We studied how the choice of binder and the slurry mixing duration affect the slurry and electrode properties. The key question was: “Is there a ‘Goldilocks zone’ of slurry parameters such as viscosity, particle size, mixing duration and dispersion stability?” Such a set of parameters might be invaluable to obtain crack‐free electrodes with high adhesive strength, resilience against severe volume changes, minimal impedance to charge–transfer, and high cycling performance in the context of Li–S batteries. To address this question, we prepared three sets of slurries using CMC, LiPAA, and PVDF binders and extensively studied how their properties evolved over a period of 4 weeks of simultaneous mixing and milling in a jar roller mill. We then observed how the electrodes prepared from these slurries varied in their microstructural, mechanical and electrochemical properties. Our results show contrasting behavior of the three binder systems from each other and indicate a complex interplay of competing and complementary factors holistically affecting the electrode properties.