Positive Electrode Active Material, Lithium-Ion Secondary Battery, Electronic Device, Vehicle, And Method For Fabricating Composite Oxide

Abstract

A highly safe or reliable secondary battery with high charge and discharge capacity is provided. Alternatively, a positive electrode active material in which a decrease in discharge capacity in charge and discharge cycles is inhibited, and a secondary battery using the positive electrode active material is provided. The positive electrode active material can be used for a lithium-ion secondary battery and includes lithium cobalt oxide containing an additive element; a battery including a positive electrode including the positive electrode active material and a lithium counter electrode is fabricated; when a charge and discharge cycle test is performed, the positive electrode active material shows the maximum discharge capacity in a 6th cycle to a 40th cycle; in the charge and discharge cycle test, for charging, constant current charging is performed at 0.5 C until 4.7 V and then constant voltage charging is performed for the shorter of a time until three hours pass or a time until the current value reaches 0.05 C; for discharging, constant current discharging is performed at 0.5 C for the shorter of a time until three hours pass or a time until the cell voltage reaches 2.5 V; 1C is set to 200 mA/g; and the measurement environment temperature is set to 25° C.

Dependencies are inferred from the claim text.