Effect of mixing sequences on the electrode characteristics of lithium-ion rechargeable batteries

Measurements are made of the viscosity of a liquid-phase slurry by varying the mixing sequences, during the preparation of a positive electrode for a lithium-ion rechargeable battery. The slurry consisted of active material powder, conductive agent powder, polymer binder solution, and liquid solvent. The slurry viscosities are analyzed through consideration of the suspension rheology. The half-cell characteristics of a positive electrode prepared from the slurry are also investigated. Although the same materials and the same contents are used, the slurries show different scales of viscosity that reflect different dispersion states of the solid particles. Accordingly, the half-cell exhibits different discharge characteristics. The best discharge capacity, in terms of stability during repeated cycle, is obtained by dry-mixing the powders and then adding binder solution and solvent in sequence.