11. A method for preparing a carbonate precursor compound according to claim 2 or 3, <u>the</u> precursor compound having a sodium to sulfur molar ratio (Na/S) of 0.4<Na/S<2, and having a sum (2* Na<sub>wt</sub>)+ S<sub>wt</sub> of the sodium (Na<sub>wt</sub>) and sulfur (S<sub>wt</sub>) content expressed in wt% of more than 0.4 wt% and less than 1.6 wt%, comprising the steps of:
- providing a feed solution comprising Ni-, Mn- and Co-ions, and a source of A, wherein the Ni-, Mn-, Co- and A-ions are present in a water soluble sulfate compound,
- providing an ionic solution comprising a carbonate solution and Na-ions, wherein the CO3/SO4ratio is selected so as to obtain the Na/S molar ratio of the precursor compound,
- providing a slurry comprising seeds comprising M'-ions, wherein M' = Nix'Mny'Coz'A'n',
A' being a dopant, with 0≤x'≤1, 0≤y'≤1, 0≤z'≤1, 0≤n'≤1 and x'+y'+z'+n'=1,
- mixing the feed solution, the ionic solution and the slurry in a reactor, thereby obtaining a reactive liquid mixture,
- precipitating a carbonate onto the seeds in the reactive liquid mixture, thereby obtaining a reacted liquid mixture and the carbonate precursor, and
- separating the carbonate precursor from the reacted liquid mixture.
sodium (Na<sub>wt</sub>) and sulfur
content
more than 0.4 wt% and less than 1.6 wt%
wt%