A method of manufacturing a cathode material for a lithium ion cell comprises: generating a lithium nickel composite oxide material in a manufacturing process, wherein the manufacturing process results in residual lithium being present in the lithium nickel composite oxide material; washing the lithium nickel composite oxide material to remove at least part of the residual lithium, wherein the washing provides the lithium nickel composite oxide material with a moisture content; and drying the lithium nickel composite oxide material to remove at least part of the moisture content, the drying performed in an environment of substantially only an inert gas or air essentially free of carbon dioxide.