NOVELTY - The positive electrode active material consists of powder-form lithium transition metal complex oxide. The mode value of particle diameter (Ra) of the active material, is greater than or equal to 0.5 microns. Particle size distribution (PSD) (x) of active material is -2.7 to -1.2. PSD is calculated from ratio of difference between arithmetic standard deviation (Rc in microns) of active material and Ra, and maximum particle diameter (Rb in microns) adjoining to Ra.    USE - For positive electrode material used for positive electrode of lithium secondary battery (all claimed) in notebook personal computer, pen input personal computer, mobile personal computer, electronic book player, mobile telephone, portable facsimile, portable copier, portable printer, headphones stereo, video movie, liquid crystal television, handy cleaner, portable compact disc, minidisk, transceiver, electronic notebook, calculator, memory card, portable tape recorder, radio, backup power supply, motor, luminaire, toy, game machine device, clock, electronic flash, camera, electric vehicle and hybrid vehicle.    ADVANTAGE - The positive electrode active material prevents the generation of crack at high temperature environment. The positive electrode provides lithium secondary battery with excellent high temperature cycle property.    DETAILED DESCRIPTION - The positive electrode active material consists of powder-form lithium transition metal complex oxide. The mode value of particle diameter (Ra) of the active material, is greater than or equal to 0.5 microns. The particle size distribution (x) of active material, after performing compression processing for 1 minute under pressure of 40 MPa, is -2.7 to -1.2. The particle size distribution is calculated from ratio ((Rc-Ra)/Rb) of difference between arithmetic standard deviation (Rc in microns) of active material and Ra, and maximum particle diameter (Rb in microns) adjoining to Ra. The lithium transition metal complex oxide is lithium-nickel-type complex oxide of formula: LiaNibMcO2.    a=0.9-1.2;    b=0.3-1.2;    b+c=0.3-1.2; and    M=beryllium, boron, magnesium, aluminum, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, copper, zinc and/or gallium.    INDEPENDENT CLAIMS are included for the following:    (1) manufacture of positive electrode active material;    (2) positive electrode material;    (3) positive electrode; and    (4) lithium secondary battery.    DESCRIPTION OF DRAWING(S) - The graph shows the particle size distribution of the positive electrode active material after compression processing. (Drawing includes non-English language text).