Positive active material, method of preparing the same, and lithium battery including the positive active material

A method of preparing a positive active material, the method comprising:

• obtaining a first mixture by mixing a Ni-containing material, a Co-containing material, and a Mn-containing material with a first solvent;
• obtaining a second mixture by removing the first solvent from the first mixture and adding a Li-containing material to the first mixture;
• and
• thermally treating the second mixture.

A method of preparing a positive active material, the method comprising:

• obtaining a third mixture by mixing a nickel (Ni)-containing material, a cobalt (Co)-containing material, a manganese (Mn)-containing material, and a lithium (Li)-containing material with a second solvent;
• obtaining a fourth mixture by removing the second solvent from the third mixture;
• and
• subjecting the fourth mixture to thermal treatment.

A lithium battery, comprising:

• a positive electrode comprising a positive active material comprised of single particles each being represented by Formula 1;
• a negative electrode;
• and
• an electrolyte imposed between the positive and negative electrodes, wherein
• Formula 1 is
• Lix(NipCoqMnr)Oy,
• wherein in Formula 1, 0.95≦x≦1.05, 0<p<1, 0<q<1, 0<r<1, p+q+r=1, and 0<y≦2.025.