Positive active material for rechargeable lithium battery and rechargeable lithium battery including same
A positive active material including a core including a lithium intercalation compound and a coating compound on a surface of the core, the coating compound including Li 2 MO 3 and a solid electrolyte compound represented by Chemical Formula 1 [Li 1.3+4x Al 0.3 M 1.7−x (PO 4 ) 3 ], wherein 0≤x≤0.7, and M is an element selected from Ti, Cr, Ga, Fe, Sc, In, Y, La, Mg, Sr, and combinations thereof; and a rechargeable lithium battery includes the positive active material.
1. A positive active material for a rechargeable lithium battery, comprising:
a particle core including a lithium intercalation compound, and
a layer of island particles on the particle core, an island particle of the island particles comprising a coating compound comprising: Li 2 MO 3 ; a solid electrolyte represented by Chemical Formula 1; and AlPO 4 :
Li 1.3+4x Al 0.3 M 1.7−x (PO 4 ) 3 , [Chemical Formula 1]
wherein in Chemical Formula 1, 0≤x≤0.7, and
wherein M is an element selected from Ti, Cr, Ga, Fe, Sc, In, Y, La, Mg, Sr, and combinations thereof,
the solid electrolyte represented by Chemical Formula 1 is mixed with the Li 2 MO 3 to a mixing ratio of about 100:0.1 wt % to about 100:3 wt %, and
an amount of the AlPO 4 is 0.25 wt % to 0.35 wt % with respect to 100 wt % of the coating compound.
2. The positive active material of claim 1 , wherein the coating compound is present in a layered phase on the surface of the particle core.
3. The positive active material of claim 1 , wherein the particle core further comprises Li 2 MO 3 , wherein M is an element selected from Ti, Cr, Ga, Fe, Sc, In, Y, La, Mg, Sr, and combinations thereof.
4. The positive active material of claim 1 , wherein an amount of the coating compound is about 0.1 wt % to about 10 wt % based on 100 wt % of the positive active material.
5. The positive active material of claim 1 , wherein a specific surface area of the positive active material is about 0.1 m 2 /g to about 0.3 m 2 /g.
6. The positive active material of claim 1 , wherein the positive active material is prepared by:
mixing a lithium-containing compound, an aluminum-containing compound, an M-containing compound, a phosphate salt, a stabilizer, and a solvent to prepare a mixed solution;
adding a lithium intercalation compound to the mixed solution to obtain a mixture; and
drying and sintering the mixture.
7. The positive active material of claim 6 , wherein the stabilizer is acetic acid, acetylacetone, oxalic acid, citric acid, or a combination thereof.
8. A rechargeable lithium battery comprising:
a positive electrode comprising the positive active material of claim 1 ;
a negative electrode comprising a negative active material; and
an electrolyte.