Methods for preparing positive electrode material for rechargeable lithium ion batteries

Abstract

A method for preparing a powderous positive electrode material comprising single crystal monolithic particles and having a general formula Li((Ni(NiMn)Co)A)O, wherein A is a dopant, −0.03≤a≤0.06, 0.05≤x≤0.35, 0.10≤z≤0.95, x+y+z=1 and k≤0.05 is described. The method comprises providing a mixture comprising a Ni- and Co- bearing precursor and a Li bearing precursor, subjecting the mixture to a multiple step sintering process whereby in the final sintering step a sintered lithiated intermediate material is obtained comprising agglomerated primary particles having a primary particle size distribution with a D50 between 2.0 and 8.0 μm, subjecting the lithiated intermediate material to a wet ball milling step to deagglomerate the agglomerated primary particles and obtain a slurry comprising deagglomerated primary particles, separating the deagglomerated primary particles from the slurry, and heat treating the deagglomerated primary particles at a temperature between 300° C. and at least 20° C. below the temperature in the final sintering step.