CPC H01M 4/366 (2013.01) [H01M 4/0471 (2013.01); H01M 4/505 (2013.01); H01M 4/525 (2013.01); H01M 10/0525 (2013.01); H01M 2004/028 (2013.01); H01M 2220/20 (2013.01)] | 9 Claims |
1. A positive electrode active material powder suitable for lithium-ion batteries, comprising lithium transition metal-based oxide particles comprising
a core and
a surface layer, said surface layer being on top of said core,
said particles comprising the elements: Li, a metal M′ and oxygen, wherein the metal M′ has a formula: M′=(NizMnyCox)1-kAk, wherein A is a dopant, 0.50≤z≤0.89, 0.05≤y≤0.25, 0.05≤x≤0.25, x+y+z+k=1, and k≤0.01,
said positive electrode active material powder having a median particle size D50 ranging from 3 μm to 15 μm and a surface layer thickness ranging from 5 nm to 200 nm,
said surface layer comprising aluminum in a content superior or equal to 0.04 wt % and inferior or equal to 0.15 wt % with respect to the total weight of the positive electrode active material powder, and having an AI surface coverage A1/A2 that is superior or equal to 100, wherein A1 is an atomic ratio Al/(Ni+Mn+Co+Al+S) of the elements Al, Ni, Mn, Co, and S contained in the surface layer, said atomic ratio A1 obtained by XPS spectrum analysis, and wherein A2 is an atomic ratio Al/(Ni+Mn+Co+Al+S) of the elements Al, Ni, Mn, Co, and S contained in the surface layer, obtained by ICP;
said surface layer comprising a LiAIO2 phase and a LiM “O2 phase with M” comprising Al, Ni, Mn, and Co,
said LiAIO2 phase being present in said surface layer in a content which is superior or equal to 0.10at % and inferior or equal to 0.30at % with respect to the total atomic content of M′ of the positive electrode active material powder,
said LiM ″O2 phase being present in a content which is superior to 0.00at % and inferior to 0.14at % with respect to the total atomic content of M′ of the positive electrode active material powder.
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