Mixed metal hydroxides, their preparation and use

Powdery composite metal hydroxide containing the metals nickel, cobalt and aluminum, wherein the powder particles have a core of nickel-cobalt hydroxide, the surface of which is coated with amorphous aluminum hydroxide. A process for the continuous manufacture of such mixed metal hydroxides by precipitation of aluminum hydroxide in the presence of a nickel-cobalt mixed hydroxide in a tubular reactor. Use of the mixed metal hydroxides for the production of active materials for positive electrodes of a secondary battery.