Composite cathode active material for lithium battery, cathode for lithium battery including the same, and lithium battery including the cathode
A composite cathode active material for a lithium battery, the composite cathode active material including: a lithium composite oxide; and a coating layer disposed on at least a portion of the lithium composite oxide and including a composite including ZrP 2 O 7 and LiZr 2 (PO 4 ) 3 , wherein the composite including ZrP 2 O 7 and LiZr 2 (PO 4 ) 3 is a reaction product of an acid treated a zirconium precursor, a phosphorus precursor, and the lithium composite oxide.
1. A composite cathode active material for a lithium battery, the composite cathode active material comprising:
a lithium composite oxide; and
a coating layer disposed on at least a portion of the lithium composite oxide and comprising a composite comprising ZrP 2 O 7 and LiZr 2 (PO 4 ) 3 ,
wherein the composite comprising ZrP 2 O 7 and LiZr 2 (PO 4 ) 3 is a reaction product of an acid-treated zirconium precursor, a phosphorus precursor, and the lithium composite oxide.
2. The composite cathode active material of claim 1 , wherein the composite comprising ZrP 2 O 7 and LiZr 2 (PO 4 ) 3 is a product of drying and heat-treating a mixture of the acid-treated zirconium precursor, the phosphorus precursor, and the lithium composite oxide.
3. The composite cathode active material of claim 1 , wherein the composite comprising ZrP 2 O 7 and LiZr 2 (PO 4 ) 3 is a reaction product of heat treatment at about 700° C. or greater.
4. The composite cathode active material of claim 1 , wherein the coating layer further comprises at least one Li 2 ZrP 2 O 8 , Zr 2 P 2 O 9 , ZrO 2 , or Li 2 ZrO 3 .
5. The composite cathode active material of claim 1 , wherein an amount of ZrP 2 O 7 in the composite comprising ZrP 2 O 7 and LiZr 2 (PO 4 ) 3 is from about 0.2 mole to about 2 moles, based on 1 mole of LiZr 2 (PO 4 ) 3 .
6. The composite cathode active material of claim 1 , wherein an amount of P in the composite is from about 0.1 mole to about 10 moles, based on 1 mole of Zr.
7. The composite cathode active material of claim 1 , wherein an amount of the composite comprising ZrP 2 O 7 and LiZr 2 (PO 4 ) 3 is from about 0.1 weight percent to about 10 weight percent, based on a total weight of the composite cathode active material.
8. The composite cathode active material of claim 1 , wherein, in the coating layer, the LiZr 2 (PO 4 ) 3 is adjacent to the lithium composite oxide.
9. The composite cathode active material of claim 1 , wherein the coating layer is a continuous film.
10. The composite cathode active material of claim 1 , wherein the lithium composite oxide comprises at least one of a layered oxide, an olivine-containing oxide, or a spinel-phase oxide.
11. The composite cathode active material of claim 1 , wherein the lithium composite oxide comprises at least one of Formulae 1 to 6 below:
Li a Ni x Co y Mn z M c O 2-e A e Formula 1
wherein, in Formula 1, 1.0≤a≤1.4, 0<x<1, 0≤y<1, 0<z<1, 0≤c<1, 0<x+y+z+c≤1, and 0≤e<1;
M is at least one V, Mg, Ga, Si, W, Mo, Fe, Cr, Cu, Zn, Ti, Al, or B; and
A is at least one anion element selected from F, S, Cl, or Br,
Li[Co 1-x M x ]O 2-b A b Formula 2
wherein, in Formula 2, 0≤b≤0.1 and 0≤x≤0.1;
M is at least one of Mg, Al, Ni, Mn, Zn, Fe, Cr, Ga, Mo, or W; and
A is at least one of F, S, Cl, or Br,
Li 1+a [Ni 1-x M x ]O 2-b A b Formula 3
wherein, in Formula 3, 0≤a≤0.2, 0≤b≤0.1, and 0.01≤x≤0.5;
M is at least one of Mg, Al, Co, Mn, Zn, Fe, Cr, Ga, Mo, or W; and
A is at least one of F, S, Cl, or Br,
Li 1+a [Mn 2-x M x ]O 4-b A b Formula 4
wherein, in Formula 4, 0≤a≤0.15, 0≤b≤0.1, and 0≤x≤0.1;
A is at least one of F, S, Cl, or Br, and
M is at least one of Co, Ni, Cr, Mg, Al, Zn, Mo, or W,
LiM x Fe 1-x PO 4 Formula 5
wherein, in Formula 5, M is at least one of Co, Ni, or Mn; and 0≤x≤1,
Li 1+a [Ni 0.5 Mn 1.5-x M x ]O 4-b A b Formula 6
wherein, in Formula 6, 0≤a≤0.15, 0≤b≤0.1, and 0≤x≤0.1;
A is at least one of F, S, Cl, or Br; and
M is at least one of Co, Ni, Cr, Mg, Al, Zn, Mo, or W.
12. The composite cathode active material of claim 1 , wherein the lithium composite oxide comprises a compound represented by Formula 7 below:
Li a Ni x Co y Mn z M c O 2-b A b Formula 7
wherein, in Formula 7, 1.0≤a≤1.4, 0<x<1, 0≤y<1, 0<z<1, 0≤c<1, 0<x+y+z+c≤1, and 0≤b≤0.1;
M is at least one of V, Mg, Ga, Si, W, Mo, Fe, Cr, Cu, Zn, Ti, Al, or B; and
A is at least one of F, S, Cl, or Br.
13. The composite cathode active material of claim 1 , wherein the lithium composite oxide is a layered compound represented by Formula 8 below:
Li a Ni x Co y Mn z O 2-b A b Formula 8
wherein, in Formula 8, 1.0≤a≤1.4, 0.7≤x≤1, 0≤y<1, 0<z<1, 0<x+y+z≤1, and 0≤b≤0.1;
M is at least one of V, Mg, Ga, Si, W, Mo, Fe, Cr, Cu, Zn, Ti, Al, or B; and
A is at least one of F, S, Cl, or Br.
14. The composite cathode active material of claim 1 , wherein the lithium composite oxide comprises at least one of Li 1.015 Ni 0.8 Co 0.15 Mn 0.05 O 2 , Li 1.015 Ni 0.8 Co 0.1 Mn 0.1 O 2 , Li 1.015 Ni 0.7 Co 0.2 Mn 0.1 O 2 , Li 1.015 Ni 0.7 Co 0.25 Mn 0.05 O 2 , Li 1.015 Ni 0.9 Co 0.05 Mn 0.05 O 2 , Li 1.015 Ni 0.91 Co 0.06 Mn 0.03 O 2 , Li 1.015 Ni 0.88 Co 0.06 Mn 0.06 O 2 , LiNi 0.8 Co 0.15 Mn 0.05 O 2 ; Li 1.08 Ni 0.8 Co 0.15 Mn 0.05 O 2 , Li 1.08 Ni 0.8 Co 0.1 Mn 0.1 O 2 , Li 1.08 Ni 0.7 Co 0.2 Mn 0.1 O 2 , Li 1.08 Ni 0.7 Co 0.25 Mn 0.05 O 2 , Li 1.08 Ni 0.9 Co 0.05 Mn 0.05 O 2 , Li 1.08 Ni 0.91 Co 0.06 Mn 0.03 O 2 , Li 1.08 Ni 0.88 Co 0.06 Mn 0.06 O 2 ; LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.7 Co 0.2 Mn 0.1 O 2 , LiNi 0.7 Co 0.25 Mn 0.05 O 2 , LiNi 0.9 Co 0.05 Mn 0.05 O 2 , LiNi 0.91 Co 0.06 Mn 0.03 O 2 , LiNi 0.88 Co 0.06 Mn 0.06 O 2 ; Li 1.1 Ni 0.8 Co 0.15 Mn 0.05 O 2 , Li 1.1 Ni 0.8 Co 0.1 Mn 0.1 O 2 , Li 1.1 Ni 0.7 Co 0.2 Mn 0.1 O 2 , Li 1.1 Ni 0.7 Co 0.25 Mn 0.05 O 2 , Li 1.15 Ni 0.9 Co 0.05 Mn 0.05 O 2 , Li 1.1 Ni 0.91 Co 0.06 Mn 0.03 O 2 , Li 1.1 Ni 0.88 Co 0.06 Mn 0.06 O 2 ; Li 1.15 Ni 0.8 Co 0.15 Mn 0.05 O 2 , Li 1.15 Ni 0.8 Co 0.1 Mn 0.1 O 2 , Li 1.15 Ni 0.7 Co 0.2 Mn 0.1 O 2 , Li 1.15 Ni 0.7 Co 0.25 Mn 0.05 O 2 , Li 1.15 Ni 0.9 Co 0.05 Mn 0.05 O 2 , Li 1.15 Ni 0.91 Co 0.06 Mn 0.03 O 2 , Li 1.15 Ni 0.88 Co 0.06 Mn 0.06 O 2 ; Li 1.2 Ni 0.8 Co 0.15 Mn 0.05 O 2 , Li 1.2 Ni 0.8 Co 0.1 Mn 0.1 O 2 , Li 1.2 Ni 0.7 Co 0.2 Mn 0.1 O 2 , Li 1.2 Ni 0.7 Co 0.25 Mn 0.05 O 2 , Li 1.2 Ni 0.9 Co 0.05 Mn 0.05 O 2 , Li 1.2 Ni 0.91 Co 0.06 Mn 0.03 O 2 , Li 1.2 Ni 0.88 Co 0.06 Mn 0.06 O 2 ; Li 1.3 Ni 0.8 Co 0.15 Mn 0.05 O 2 , Li 1.3 Ni 0.8 Co 0.1 Mn 0.1 O 2 , Li 1.3 Ni 0.7 Co 0.2 Mn 0.1 O 2 , Li 1.3 Ni 0.7 Co 0.25 Mn 0.05 O 2 , Li 1.3 Ni 0.9 Co 0.05 Mn 0.05 O 2 , Li 1.3 Ni 0.91 Co 0.06 Mn 0.03 O 2 , Li 1.3 Ni 0.88 Co 0.06 Mn 0.06 O 2 ; Li 1.4 Ni 0.8 Co 0.15 Mn 0.05 O 2 , Li 1.4 Ni 0.8 Co 0.1 Mn 0.1 O 2 , Li 1.4 Ni 0.7 Co 0.2 Mn 0.1 O 2 , Li 1.4 Ni 0.7 Co 0.25 Mn 0.05 O 2 , Li 1.4 Ni 0.9 Co 0.05 Mn 0.05 O 2 , Li 1.4 Ni 0.91 Co 0.06 Mn 0.03 O 2 , Li 1.4 Ni 0.88 Co 0.06 Mn 0.06 O 2 ; Li 1.5 Ni 0.8 Co 0.15 Mn 0.05 O 2 , Li 1.5 Ni 0.8 Co 0.1 Mn 0.1 O 2 , Li 1.5 Ni 0.7 Co 0.2 Mn 0.1 O 2 , Li 1.5 Ni 0.7 Co 0.25 Mn 0.05 O 2 , Li 1.5 Ni 0.9 Co 0.05 Mn 0.05 O 2 , Li 1.5 Ni 0.91 Co 0.06 Mn 0.03 O 2 , or Li 1.5 Ni 0.88 Co 0.06 Mn 0.06 O 2 .
15. The composite cathode active material of claim 1 , wherein an amount of free lithium in the composite cathode active material is about 3,000 parts per million or less, and
wherein the composite cathode active material has a discharge capacity of about 200 milliampere hours per gram or more.
16. The composite cathode active material of claim 1 , wherein the coating layer has a thickness of about 1 nanometer to about 1 micrometer.
17. A method of preparing a composite cathode active material, the method comprising:
providing an acidic zirconium precursor mixture comprising a zirconium precursor, a solvent, and an acid;
providing a phosphorus precursor mixture comprising a phosphorus precursor and a solvent;
mixing a lithium composite oxide with the acidic zirconium precursor mixture and the phosphorus precursor mixture;
drying the mixture of the lithium composite oxide, the acidic zirconium precursor mixture, and the phosphorus precursor mixture to form a dried product; and
heat-treating the dried product to prepare the composite cathode active material,
wherein the composite cathode active material comprises:
a lithium composite oxide; and
a coating layer disposed on at least a portion of the lithium composite oxide and comprising a composite comprising ZrP 2 O 7 and LiZr 2 (PO 4 ) 3 .
18. The method of claim 17 , wherein the heat-treating is performed at about 700° C. or greater in an oxidative gas atmosphere.
19. The method of claim 17 , wherein the mixing is performed at a temperature of about 25° C. to about 90° C.
20. The method of claim 17 , wherein the drying is performed at a temperature of about 30° C. to about 150° C.
21. The method of claim 17 , wherein the acidic zirconium precursor mixture has a pH of about 5 or less.
22. The method of claim 17 , wherein the acid comprises at least one of nitric acid, hydrochloric acid, or sulfuric acid.
23. The method of claim 17 , wherein a weight ratio of the solvent to the acid is from about 1:0.01 to about 1:1, and wherein an amount of the solvent is two times or less than a weight of the lithium composite oxide.
24. The method of claim 17 , wherein the zirconium precursor comprises at least one of zirconium oxynitrate, zirconium chloride, zirconium acetate, zirconium hydroxide, or zirconium nitride.
25. The method of claim 17 , wherein the phosphorus precursor comprises at least one of ammonium phosphate, triammonium phosphate trihydrate, ammonium dihydrogen phosphate, or phosphoric acid.
26. The method of claim 17 , wherein the lithium composite oxide is a layered compound represented by Formula 8 below:
Li a Ni x Co y Mn z O 2-b A b Formula 8
wherein, in Formula 8, 1.0≤a≤1.4, 0.7≤x<1, 0≤y<1, 0<z<1, 0<x+y+z≤1, and 0≤b≤0.1;
M is at least one of V, Mg, Ga, Si, W, Mo, Fe, Cr, Cu, Zn, Ti, Al, or B; and
A is at least one of F, S, Cl, or Br.
27. The method of claim 17 , wherein the lithium composite oxide is prepared by providing a precursor mixture and heat-treating the precursor mixture at a temperature of about 400° C. to about 900° C. in an inert gas atmosphere or in an oxidative gas atmosphere.
28. A cathode for a lithium battery, the cathode comprising the composite cathode active material of claim 1 .
29. A lithium battery including the cathode according to claim 28 .