Effects of pH on the dispersion and cell performance of LiCoO₂ cathodes based on the aqueous process

The effects of the pH of a water-based slurry on the dispersion homogeneity and cell performance of lithium cobalt oxide (LiCoO₂) cathodes were investigated. Based on the results of dispersion and cell performance characterizations, it is known that the pH will affect the dispersion homogeneity of cathode materials and the resulting electronic conduction, adhesion strength and C-rate capability of as-prepared electrodes. For the LiCoO₂ aqueous slurry, the as-prepared electrode sheet is homogeneous at its initial equilibrium pH of 11.6 which is a safe distance away from its iso-electric point (IEP). However, this pH value is too high; the slurry would significantly react with the aluminum substrate to damage the microstructures of the sheets and the corresponding cell performances. Hence, the pH of an as-prepared LiCoO₂ slurry should be adjusted lower and kept away from the IEP as well.