7. A method for preparing a carbonate precursor compound according to claim 1, comprising:
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 CO<sub>3</sub>/SO<sub>4 </sub>rate is selected so as to obtain a Na/S molar ratio with 0.4<Na/S<2 and the sodium (Na<sub>wt</sub>) and sulfur (S<sub>wt</sub>) content expressed in wt % yield a sum (2*Na<sub>wt</sub>)+S<sub>wt </sub>of more than 0.4 wt % and less than 1.6 wt %,
providing a slurry comprising seeds comprising M′-ions, wherein M′=NixMnyCozA′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 the 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.
Na/S molar ratio
0.4<Na/S<2
the sodium (Na<sub>wt</sub>) and sulfur (S<sub>wt</sub>) content
of more than 0.4 wt % and less than 1.6 wt %
wt %