A lithium transition metal oxide powder for use in a rechargeable battery is disclosed, where the surface of the primary particles of said powder is coated with a LiF layer, where this layer consists of a reaction product of a fluorine-containing polymer and the primary particle surface. The lithium of the LiF originates from the primary particles surface. Examples of the fluorine-containing polymer are either one of PVDF, PVDF-HFP or PTFE. Examples of the lithium transition metal oxide are either one of —LiCodMeO2, wherein M is either one of both of Mg and Ti, with e