Positive electrode for lithium secondary battery, and lithium secondary battery comprising same

A positive electrode for a lithium secondary battery, comprising:

• a positive electrode current collector, and
• a positive electrode mixture layer which is disposed on at least one surface of the positive electrode current collector and which comprises a positive electrode active material represented by Formula 2 and a positive electrode additive represented by Formula 1,
• wherein a cross-sectional structure of the positive electrode mixture layer after initial charging comprises:
• a first region having a structure filled with the positive electrode active material, and
• a second region having a needle-shaped crack structure inside and outside the positive electrode additive,
• wherein the second region accounts for 0.001 to 10% of a total cross-sectional area of the positive electrode mixture layer, and
• wherein the needle-shaped crack structure has cracks with an average thickness of 5 to 800 nm and an average length of 50 nm to 10 μm,
• LipCo(1-q)M1qO4 [Formula 1]
• wherein in Formula 1,
• M1 is one or more elements selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and
• p and q are 5≤p<7 and 0≤q≤0.5, respectively
• Lix[NiyCozMnwM2v]Ou [Formula 2]
• wherein in Formula 2,
• M2 is one or more elements selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and
• x, y, z, w, v and u are 1.0≤x≤1.30, 0.1≤y<0.95, 0.01<z≤0.5, 0.01<w≤0.5, 0≤v≤0.2, 1.5≤u≤4.5, respectively.