SLURRY STORAGE DEVICE, SLURRY PRODUCTION SYSTEM AND SLURRY STORAGE METHOD

A slurry storage device that stores an aqueous slurry containing a high nickel material prepared by a dispersion device which mixes a powder and a solvent, the device includes a holding unit that holds the aqueous slurry, and a pH value rise suppressing unit that suppresses a rise in a pH value of the aqueous slurry.