The effect of poly(acrylic acid) ammonium(PAA-NH4) dispersant on high solids loading and stable silicon suspensions was characterized.The slurry of 50 vol% solids loading with low viscosity and high zeta potential was obtained using the concentration of PAA-NH4 of 0.020-0.030 g/mL in the premix solution.Absorption curve was measured and the absorption modality of PAA-NH4,onsilicon particles was discussed.