A method for making a coated electrode material for a lithium rechargeable electrochemical cell (10) includes the steps of mixing (65) Co and Li salts, then either dissolving (70) the Li and Co salts in water to form a solution or heating (70) the salts to form a melt. A lithium nickel oxide material is mixed (80) with the solution or the melt to form a mixture, and the mixture is dried (85) to result in LiCoO.sub.2 -coated LiNiO.sub.2. Increased performance can be achieved by including a post-treatment step in which the LiCoO.sub.2 -coated LiNiO.sub.2 is heated (90) to about 700.degree. C.