| CPC H01M 4/525 (2013.01) [H01M 4/0471 (2013.01); H01M 4/366 (2013.01); H01M 10/0525 (2013.01); H01M 10/0568 (2013.01); H01M 10/0569 (2013.01); H01M 50/40 (2021.01); H01M 2300/002 (2013.01)] | 20 Claims |
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1. A method for preparing a stabilized layered lithium metal oxide material comprising the sequential steps of:
(a) continuously adding an alkali metal hydroxide solution, an aqueous ammonium hydroxide solution and an aqueous solution of metal salts comprising a nickel salt, a manganese salt, a cobalt salt, or a combination of two or more thereof, to a stirring reactor at a temperature of about 25 to 60° C., at hydroxide addition rates sufficient to maintain a constant pH of greater than or equal to 11 in the reactor, thereby coprecipitating metal hydroxide core precursor particles; and halting the additions of the solutions when the average particle size of the core precursor particles reaches a selected target size;
(b) continuously adding an aqueous coating solution comprising a manganese salt, a cobalt salt, or a combination thereof, to a stirring slurry of the core precursor particles formed in step (a) without addition of any hydroxide and without controlling the pH, at a temperature of about 25 to 60° C.; thereby coprecipitating cobalt and manganese hydroxide on the surface and interior of the core precursor particles to form coated precursor particles; and halting addition of the coating solution when the pH drops by a selected target level of about 0.1 to 1 pH units;
(c) recovering the coated precursor particles;
(d) mixing the recovered coated precursor particles with at least one molar equivalent of lithium hydroxide relative to the total moles of metal hydroxide in the coated precursor particles to produce a precursor mixture; and
(e) calcining the precursor mixture from step (d) at a temperature in the range of about 725 to 900° C. for about 4 to 50 hours, to form the stabilized lithium metal oxide material.
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