abstract |
In the present invention, Na, M 1 and M 2 (wherein M 1 represents at least one element selected from the group consisting of Mg, Ca, Sr and Ba, and M 2 is a group consisting of Mn, Fe, Co and Ni). A molar ratio of Na: M 1 : M 2 is a: b: 1 (where a is a value in the range of 0.5 or more and less than 1, and b is greater than 0 and less than 0.5) It is a value of the range of, and a + b is a value of the range of more than 0.5 and 1 or less). The present invention relates to an electrode active material containing the composite metal oxide. The present invention relates to an electrode containing the electrode active material. The present invention relates to a sodium secondary battery having the electrode as a positive electrode. |