Positive active material for rechargeable lithium battery, positive electrode including same and rechargeable lithium battery including same

A positive active material for a rechargeable lithium battery, comprising:

• a first positive active material and a second positive active material mixed together,
• wherein the first positive active material is a mixture of a first nickel-based lithium composite oxide and a second nickel-based lithium composite oxide, the first nickel-based lithium composite oxide and the second nickel-based lithium composite oxide having different average particle diameters,
• the second positive active material is represented by Chemical Formula 2 and has an average particle diameter of about 300 nm to about 600 nm:
• Lia1Fe1-x1M1x1 PO4, [Chemical Formula 2]
• wherein, in Chemical Formula 2, 0.90≤a1≤1.8, 0≤x1≤0.7, and M1 is magnesium (Mg), cobalt (Co), nickel (Ni), or a combination thereof,
• an amount of the first positive active material is about 90 wt % to about 98 wt % based on a total amount of the positive active material for a rechargeable lithium battery, and
• an amount of the second positive active material is about 2 wt % to about 10 wt % based on a total amount of the positive active material for a rechargeable lithium battery.