Active materials for the positive electrode in alkaline storage battery and the manufacturing method of them

摘要

The energy density of active materials for a positive electrode comprising an oxide containing Ni as a main metallic element is enhanced, and, moreover, a method for manufacturing them is provided. The oxide includes Ni as a main metallic element and contains at least Mn in the state of solid solution or eutectic mixture, wherein the average valence of Mn is 3.3 valences or more, the tap density is 1.7 g/cc or more, the half width of a peak at around 2 theta =37-40 DEG of X-ray diffraction using CuK alpha ray is 1.2 deg or less, the ratio B/A of integrated intensity B of a peak at around 2 theta =18-21 DEG to integrated intensity A of a peak at around 2 theta =37-40 DEG is 1.25 or less, and the volume of pores having a pore radius of 40 ANGSTROM or less is 60% or more of the total pore volume. The oxide is obtained by growing in the state of keeping the dissolved oxygen concentration in the aqueous solution in the reaction vessel and then oxidizing the oxide.