FIELD: electrochemistry.
SUBSTANCE: invention relates to the active material of a positive electrode and a battery containing the active material of a positive electrode. The active material of the positive electrode has a granular form and contains as an essential component a complex lithium oxide and a transition metal containing at least manganese as a transition metal element and having a layered structure of rock salt. The concentration difference between the average Mn concentration and the local maximum Mn concentration is equal to or less than 4 at. %. The average concentration of Mn is measured on the basis of spectroscopic analysis of the emission of inductively coupled plasma of the active material of the positive electrode, and the maximum local concentration of Mn is measured on the basis of energy-dispersive X-ray spectral analysis using a transmission electron microscope.
EFFECT: increase in the durability of the battery, an improvement in the characteristics of the battery (a decrease in internal resistance).
6 cl, 2 dwg, 13 ex
