A lithium positive electrode active material intermediate comprising less than 80 wt % spinel phase and a net chemical composition of LixNiyMn2-yO4-δ wherein 0.9≤x≤1.1; 0.4≤y≤0.5; and 0.1≤δ; where the lithium positive electrode active material intermediate has been heat treated in a reducing atmosphere at a temperature of from 300° C. to 1200° C. A process for the preparation of a lithium positive electrode active material with high tap density for a high voltage secondary battery where the cathode is fully or partially operated above 4.4 V vs. Li/Li+, comprising the steps of a) heating a precursor in a reducing atmosphere at a temperature of from 300° C. to 1200° C. to obtain a lithium positive electrode active material intermediate; b) heating the product of step a. in a non-reducing atmosphere at a temperature of from 300° C. to 1200° C.