Precursor and method for preparing Ni based Li transition metal oxide cathodes for rechargeable batteries

A crystalline precursor compound is described for manufacturing a lithium transition metal based oxide powder usable as an active positive electrode material in lithium-ion batteries, the precursor having a general formula Li1−a ((Niz(Ni1/2 Mn1/2)y Cox)1−k Ak)1+a O2, wherein x+y+z=1, 0.1≤x≤0.4, 0.25≤z≤0.55, A is a dopant, 0≤k≤0.1, and 0.04≤a≤0.50, wherein the precursor has a crystalline size L expressed in nm, with 77−(67*z)≤L≤97−(67*z). Also a method is described for manufacturing a positive electrode material having a general formula Li1−a′ ((Niz (Ni1/2 Mn1/2)y Cox)1−k Ak)1−a′ O2, wherein x+y+z=1, 0.1≤x≤0.4, 0.25≤z≤0.55, A is a dopant, 0≤k≤0.1, and 0.01≤a′≤0.10 by sintering the crystalline precursor compound in an oxidizing atmosphere at a temperature T between 800 and 1000° C., for a time t between 6 and 36 hrs.