USE OF A POSITIVE ELECTRODE MATERIAL IN A SODIUM BATTERY, AND SODIUM BATTERY COMPRISING SAID POSITIVE ELECTRODE ACTIVE MATERIAL

The invention provides a positive electrode active material for sodium batteries which has a high working potential and can be charged and discharged at a high potential. The invention also provides a method of producing such a positive electrode active material, with this positive electrode active material for sodium batteries being represented by general formula (1) below: Na x M y (AO 4 ) z (P 2 O 7 ) w (1) (wherein M is at least one selected from the group consisting of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper and zinc; A is at least one selected from the group consisting of aluminum, silicon, phosphorus, sulfur, titanium, vanadium and tungsten; x satisfies the condition 4 ¥ x ¥ 2; y satisfies the condition 4 ¥ y ¥ 1, z satisfies the condition 4 ¥ z ¥ 0; w satisfies the condition 1 ¥ w ¥ 0; and one or both of z and w is 1 or more).