COMPOSITE METAL OXIDE, ELECTRODE, AND SODIUM SECONDARY BATTERY

摘要

Disclosed is a composite metal oxide which contains Na, M1 and M2 [wherein M1 represents at least one element selected from the group consisting of Mg, Ca, Sr and Ba; and M2 represents at least one element selected from the group consisting of Mn, Fe, Co and Ni], wherein the molar ratio Na:M1:M2 is a:b:1 [wherein a represents a value of not less than 0.5 and less than 1; and b represents a value more than 0 and not more than 0.5, wherein the sum total of a and b (i.e., a + b) is more than 0.5 and not more than 1]. Also disclosed is an electrode active material comprising the composite metal oxide. Further disclosed is an electrode comprising the electrode active material. Still further disclosed is a sodium secondary battery involving the electrode as a positive electrode.