Cathode active material, secondary battery comprising the same, and method of manufacturing the positive active material

A positive active material comprising:

• a core comprising a lithium metal oxide capable of intercalation and deintercalation of lithium ions;
• and
• a non-conductive carbonaceous film containing oxygen on at least one portion of a surface of the core,
• wherein the non-conductive carbonaceous film comprises at least one carbon compound having a functional group of the formula C(═O)Ra, —C(═O)ORa, and —OC(═O)ORa, wherein Ra is hydrogen, a C1-C10 alkyl group, or a C6-C20 aryl group, and
• wherein an amount of carbon in the non-conductive carbonaceous film is about 0.001 part by weight to about 0.3 part by weight, based on 100 parts by weight of the core,
• wherein the core is represented by Formula 1:
• LiaMbO2-c(X1)c Formula 1
• wherein in Formula 1,
• a is 0.8≤a≤1.2, b is 0<b≤1, c is 0≤c≤1, and
• M is at least one element selected from manganese (Mn), nickel (Ni), cobalt (Co), copper (Cu), magnesium (Mg), sodium (Na), calcium (Ca), titanium (Ti), zinc (Zn), gallium (Ga), germanium (Ge), aluminum (Al), chromium (Cr), strontium (Sr), molybdenum (Mo), tungsten (W,) vanadium (V), titanium (Ti), zirconium (Zr), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), silver (Ag), gold (Au), hafnium (Hf), tin (Sn), and platinum (Pt), and
• X1 is at least one element selected from oxygen (O), fluorine (F), sulfur (S), and phosphorus (P), and
• wherein a thickness of the non-conductive carbonaceous film is about 0.1 nm to about 5.0 nm.