Effects of the Solvent Concentration (Solid Loading) on the Processing and Properties of the Composite Electrode

For various composite electrodes with the same composition 80( % , % CB, % PMMA)-20(EC-PC), and made by the solvent casting technique, the cycled capacity varies between 100 and depending on the initial volatile solvent concentration. For a concentration below the optimal one, the electrode dispersion exhibits a yield stress that inhibits flow and prevents homogeneous distribution of the constituents. Above the optimal concentration, settling of the particles in the low viscosity dispersion can create a concentration gradient. Below and above the optimal solvent concentration, the electrochemical performance is degraded due to poor electronic wiring of the active material. A generalization of this work to other materials and composite electrode formulations is discussed. In particular, satisfactory prediction of settling rate has been achieved using relations derived from Stokes' law and material parameters.