Abstract: The present invention discloses a preparation method for high density aluminum doped cobalt oxide, which comprises following steps: 1) adding a cobalt salt solution, an alkaline solution and an oxidizer to a reactor for reaction; adding an aluminum cobalt solution to the reaction system for reaction; stopping adding the aluminum cobalt solution after D50 reaches 3.5-4.0 ?m, stopping the reaction when D50 reaches the desired particle size, thus obtaining aluminiferous cobalt oxyhydroxide slurry; 2) aging, dehydrating, washing and drying the aluminiferous cobalt oxyhydroxide slurry, thus obtaining aluminiferous cobalt oxyhydroxide powder; 3) calcining the aluminiferous cobalt oxyhydroxide powder, thus obtaining the target object. With the method of the present invention, doped aluminum can be perfectly embedded into cobalt oxide lattices, thus effectively enhancing the tap density and uniformity of aluminum doped cobalt oxide and improving the cycle performance and charge-discharge performance of batteries.

Abstract: The present invention discloses a preparation method for 2-4 ?m battery-grade cobalt tetroxide, comprises following steps: 1) adding a cobalt salt solution and an alkaline solution by parallel flows to a reactor with a base solution and an air flow, controlling pH value of a system by adjusting flow rate of the alkaline solution for coprecipitation reaction at a certain stirring rate, decreasing the pH value of the reaction system and increasing flow rate of the cobalt salt solution after the reaction solutions begin to overflow; 2) aging and drying the cobalt oxyhydroxide slurry in sequence; 3) calcining the dried cobalt oxyhydroxide. By adopting this method, tap density of the battery-grade cobalt tetroxide obtained is much higher than that of cobalt tetroxide with a same particle size specification prepared by the prior art.