Positive electrode for lithium secondary battery and lithium secondary battery comprising same
The present invention relates to a positive electrode for a lithium secondary battery and a lithium secondary battery comprising the same, wherein the positive electrode comprises: a current collector; an active material layer formed on the current collector and comprising a compound capable of intercalating and deintercalating lithium; and a coating layer formed on the active material layer and comprising an aqueous binder and a compound of Chemical Formula 1 having an average particle diameter (D50) of 2 μm or less. Li a Fe 1-x M x PO 4 [Chemical Formula 1] (In Chemical Formula 1, 0.90≤a≤1.8, 0≤x≤0.7, and M is Mg, Co, Ni, or a combination thereof)
1. A positive electrode for a lithium secondary battery, comprising:
a current collector;
an active material layer formed on the current collector and comprising a compound capable of intercalating and deintercalating lithium; and
a coating layer separately formed on the active material layer and comprising an aqueous binder and a compound of Chemical Formula 1 having an average particle diameter (D50, indicating a diameter of a particle where a cumulative volume is about 50 volume % in a particle distribution) of 0.2 μm to 1 μm;
the aqueous binder comprises a styrene-butadiene rubber, an acrylate-based compound, an imide-based compound, a nitrile-based compound, an acetate-based compound, a cellulose-based compound, or a cyano-based compound:
Li a Fe 1-x M x PO 4 [Chemical Formula 1]
wherein, in Chemical Formula 1, 0.90≤a≤1.8, 0≤x≤0.7, and
M is Mg, Co, Ni, or a combination thereof.
2. The positive electrode for a lithium secondary battery of claim 1 , wherein a thickness of the coating layer is 1 μm to 13 μm.
3. The positive electrode for a lithium secondary battery of claim 1 , wherein the aqueous binder is an aqueous binder having oxidation resistance.
4. The positive electrode for a lithium secondary battery of claim 1 , wherein the coating layer further comprises a thickener.
5. The positive electrode for a lithium secondary battery of claim 1 , wherein a ratio of the thickness of the active material layer to that of the coating layer is 30:1 to 10:1.
6. The positive electrode for a lithium secondary battery of claim 1 , wherein a mixing ratio of the compound of Chemical Formula 1 and the aqueous binder is 24:1 weight ratio to 50:1 weight ratio.
7. A lithium secondary battery, comprising
the positive electrode of claim 1 ;
a negative electrode comprising a negative active material, and
an electrolyte.