Cobalt hydroxide particles and manufacturing method therefor and positive electrode active material and manufacturing method therefor

The present invention obtains cobalt hydroxide particles having a high filling property and high density. The cobalt hydroxide particles, which are used as precursors to a positive electrode active material for a non-aqueous electrolyte secondary battery, are formed from spherical secondary particles in which primary particles are aggregated. The secondary particle average aspect ratio is 0.7 or more, the average particle diameter is 5-35 µm, and the value of (d90-d10)/MV, which represents the particle size distribution, is 0.6 or less. In a cross-sectional observation of the secondary particles, the ratio (N/L) of the number (N) of gaps having a maximum major axis of 0.3 µm or more confirmed inside a secondary particle having a cross-sectional major axis of 3 µm or more relative to the cross-sectional major axis (L) of the secondary particle is 1.0 or less, and the maximum major axis of the gaps is 15% or less of the cross-sectional major axis of the secondary particle.