Electrode active material with low moisture retention and lithium secondary battery including the same

A lithium secondary battery comprising:

• an anode comprising an anode active material,
• a cathode comprising a cathode active material, and
• a polymer membrane, wherein the polymer membrane is disposed between the cathode and the anode,
• wherein the anode active material comprises a mixture of at least two kinds of lithium metal oxide particles having different mass median particle diameters D50,
• wherein the lithium metal oxide particles are—consist of secondary particles comprising primary particles,
• the mixture comprises the first lithium metal oxide particles having a mass median particle diameter D50 of 700 nm to less than 1.8 μm and second lithium metal oxide particles having a mass median particle diameter D50 of 12 μm to less than 20 μm, and
• a mix ratio of the first lithium metal oxide particles to the second lithium metal oxide particles is 70:30 to 30:70,
• wherein the lithium metal oxide particles of the anode active material is composed of a lithium metal oxide represented by Formula 2 below:
• LiaTibO4 (2)
• wherein 0.5≤a≤3 and 1≤b≤2.5, and
• the cathode active material is composed of a lithium metal oxide represented by Formula 3 below:
• LixMyMn2−yO4−z,Az (3)
• wherein 0.9<x<1.2, 0<y<2, and 0<z<0.2;
• M is at least one element selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Ti, and Bi;
• and
• A is at least one monovalent or divalent anion.