NOVELTY - The positive electrode active material comprises a layered lithium metal oxide composition, and a first material. The positive electrode active material has a 10th cycle specific discharge capacity of 250-310 mAh/g at room temperature and a tap density of 2 g/mL. The specific discharge capacity is determined at a discharge rate of C/3 when discharged from 4.6-2 volts. The material comprises 0.1-4 mole percent metal fluoride. The first cycle irreversible capacity loss of the electrode material is not more than 2/3 of the first cycle irreversible capacity loss.    USE - The positive electrode active material is useful for a secondary lithium ion battery for cellular phones, lap-top computers, high energy applications such as electric vehicles, plug in hybrid electric vehicles, mobile entertainment devices and televisions.    ADVANTAGE - The positive electrode active material has high tap density and overall discharge capacities and improved material performance, and provides lithium ion batteries with improved long term cycling performance and high power output.    DETAILED DESCRIPTION - The positive electrode active material comprises a layered lithium metal oxide composition, and a first material. The positive electrode active material has a 10th cycle specific discharge capacity of 250-310 mAh/g at room temperature and a tap density of 2 g/mL. The specific discharge capacity is determined at a discharge rate of C/3 when discharged from 4.6-2 volts. The material comprises 0.1-4 mole percent metal fluoride. The first cycle irreversible capacity loss of the electrode material is not more than 2/3 of the first cycle irreversible capacity loss of an uncoated lithium metal oxide composite both cycled at discharge rate of C/10. The electrode material has 20th cycle discharge capacity of 98.5% of the 5th cycle discharge capacity when discharged at room temperature at a discharge rate of C/3, and has a tap density of 1.8 g/mL. An INDEPENDENT CLAIM is included for a secondary lithium ion battery (100).    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a lithium ion battery.    Battery (100)    Negative electrode (102)    Positive electrode (104)    Separator (106)    Current collectors. (108, 110)