POSITIVE ELECTRODE ACTIVE MATERIAL

There is provided a positive electrode active material comprising (a) a first component comprising lithium transition metal oxide spinel particles; (b) a second oxide component selected from oxides of Sr, Y, Zr, Nb, La and W, and mixtures thereof; wherein the positive electrode active material is (i) particles comprising one or more single crystals of the first component, wherein the arithmetic mean value of the minimum Feret diameter of the particles measured using scanning electron microscopy is no greater than 3 µm, wherein the second oxide component is disposed at least partly on the surface of the particles; and/or (ii) secondary particles comprising agglomerated single crystal particles of the first component, wherein the second oxide component is dispersed through the secondary particles on the surface of the single crystal particles at the interfaces between the single crystal particles.