Positive electrode active materials comprising a dopant in an amount of 0.1 to 10 mole percent of Mg, Ca, Sr, Ba, Zn, Cd or a combination thereof are described that have high specific discharge capacity upon cycling at room temperature and at a moderate discharge rate. Some materials of interest have the formula Li1+xNiαMnβ-δCoγAδXμO2−zFz, where x ranges from about 0.01 to about 0.3, δ ranges from about 0.001 to about 0.15, and the sum x+α+β+γ+δ+μ can approximately equal 1.0. The materials can be coated with a metal fluoride to improve the performance of the materials especially upon cycling. The materials generally can have a tap density of at least 1.8 g/mL. Also, the materials can have an average discharge voltage of around 3.6 V.