Critical Binder-to-Powders Coverage Ratio for Faster Graphite/SiO_x Electrode Formulation Optimization

Mastering electrodes' formulations is a complex and tedious task, because for each composition of electroactive material(s) it is necessary to adjust the inactive additives nature and content to optimize battery performance. In this direction, the amount of binder is proposed to be adjusted to the surface developed by all of the powders involved in the composition of the electrode, i.e., the electroactive materials and electronic conductive additives. This concept, introduces here as binder-to-powders coverage ratio, relies upon the micromechanical models developed in the field of polymer-based composite materials. The validity of this new electrode formulation parameter is shown here for two different SiO_x/Graphite blends, which differ in the type of graphite, and for blends of two different binders, polyacrylic acid and styrene-butadiene rubber. At the optimal coverage ratio, a satisfactory capacity retention is obtained in full cell with an ethylene carbonate free and fluoroethylene carbonate rich electrolyte.