Effects of PAA-NH4 addition on the dispersion property of aqueous LiCoO2 slurries and the cell performance of As-prepared LiCoO2 cathodes

The dispersion property of aqueous lithium cobalt oxide (LiCoO2) slurries and the corresponding cell performance of LiCoO2 electrodes with and without dispersant additions were investigated. The influence of dispersant, ammonium polyacrylic acid (PAA-NH4), and polyacrylic latex binder (LA132) on the dispersion behaviors of LiCoO2 in aqueous suspensions is characterized by zeta potential and rheology measurements. The results show that the PAA-NH4 can adsorb onto the LiCoO2 powder to provide an electrosteric stabilization in aqueous suspensions, but LA132 does not show such function. For the as-prepared LiCoO2 electrode without PAA-NH4 addition, the LiCoO2 powder agglomerates and the binder accumulates around the powder. This unfavorable phenomenon can be diminished by increasing PAA-NH4 content. However, it is found that too much addition of PAA-NH4 is detrimental to the electrochemical properties of LiCoO2. To simultaneously obtain a well- dispersed LiCoO2 and a LiCoO2 electrode with a better electrochemical property, the appropriate amount of PAA-NH4 is about 0.01 wt % based upon LiCoO2 weight. (c) 2005 The Electrochemical Society.