Island-covered lithium cobaltite oxides
AssigneeUmicore AG & Co. KG
InventorsJens Martin Paulsen, Thomas Lau
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Abstract
Disclosed is a cathode active material and a method to produce the same at low cost. The cathode powder comprises modified LiCoO2, and possibly a second phase which is LiM′O2 where M′ is Mn, Ni, Co with a stoichiometric ratio Ni:Mn≧1. The modified LiCoO2 is Ni and Mn bearing and has regions of low and high manganese content, where regions with high manganese content are located in islands on the surface. The cathode material has high cycling stability, a very high rate performance and good high temperature storage properties.
Claims23
A powderous lithium transition metal oxide comprising
- a first phase consisting of Mn and Ni bearing LiCoO2 particles, said particles having a plurality of discrete and detached Mn and Ni enriched islands partially covering surfaces thereof, wherein said islands have a Mn and Ni concentration that is higher than in the bulk of said particles and said islands comprise at least 5 mol % of Mn;
- and
- a second island-free phase having a generalized formula of Li1+aM′1−aO2±b, with −0.03<a<0.05 and b<0.02, M′=NimMnnCo1−m−n, with m≧n, and 0.1<m+n<0.9;
- wherein the first phase originates from a reaction of LiCoO2 particles and the second island-free phase.
The method of 16, wherein the Ni—Mn—Co precursor powder is a transition metal hydroxide, oxyhydroxide, carbonate, oxycarbonate, or lithium transition metal compound, wherein the transition metal composition M″ is M″=NioMnpCo1-o-p, with o+p>0.5 and o>p.
Dependencies are inferred from the claim text.