To provide a positive electrode active material which enables the suppression of the rise in resistance and the improvement of cycle characteristics, a positive electrode and a battery, and a battery pack using them, an electronic device, an electrically-powered vehicle, a power storage device and an electric power system.

A positive electrode comprises a positive electrode active material. The positive electrode active material comprises a first positive electrode material consisting of a lamellar rock salt type of lithium metal oxide including lithium, and at least one kind of metal of Ni, Co, Fe, Mn, Cu, Zn, Al, Cr, V, Ti, Mg and Zr. As a result of Rietveld analysis of a powder X-ray diffraction pattern of the first positive electrode material on the positive electrode in a discharge state, the site occupancy rate of ions of metal other than lithium at 3a-sites is 5% or less, and the site occupancy rate of ions of metal other than lithium and the at least one kind of metal occupying part of 3b-sites at the 3b-sites is 1% or more. The positive electrode active material is covered with a coating, and is exposed from the coating by 0.05-8% thereof.