A positive electrode material for lithium secondary battery

PROBLEM TO BE SOLVED: To provide a positive electrode material for lithium secondary battery that has an excellent cycle characteristic and is superior in the balance with discharge capacity. SOLUTION: The positive electrode material for lithium secondary battery contains a lithium nickel complex oxide that has C/S value of less than 0.7, when the BET specific surface area is S (m /g) and the carbonic acid concentration measured by the following measurement method is C (wt.%). The measurement method is as follows: (a) a lithium nickel complex oxide 15 mg is measured precisely in a teflon container having 30 ml value, and 5 ml ultrapure water is added, (b) this slurry is extracted for 30 minutes by an ultrasonic washer and, then, filtered using a filtration filter made of cellulose acetate having an opening hole diameter of 0.2 μm, (c) this filtered liquid 100 μl is injected into an ion chromatography analyzer (eluate: 0.1 mM octane sulfonic acid) and carbonic acid amount A (mg) is measured, and (d) the carbonic acid concentration C is obtained by the following formula: Carbonic acid concentration C=(A/15)×100.