Fluorine doped lithium rich metal oxide positive electrode battery materials with high specific capacity and corresponding batteries
View Patent ↗Lithium rich metal oxyfluorides are described with high specific capacity and, good cycling properties. The materials have particularly good high rate capabilities. The fluorine dopant can be introduced in a low temperature process to yield the materials with desirable cycling properties. In some embodiments, the positive electrode active materials have a composition represented approximately by the formula Li 1+x Ni α Mn β Co γ A δ O 2−z F z where: x is from about 0.02 to about 0.19, α is from about 0.1 to about 0.4, β is from about 0.35 to about 0.869, γ is from about 0.01 to about 0.2, δ is from 0.0 to about 0.1 and z is from about 0.01 to about 0.2, where A is Mg, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb or combinations thereof.
1. An electroactive composition comprising a layered crystalline material approximately represented by a formula Li 1+x Ni α Mn β Co γ A δ O 2−z F z , where:
x is from about 0.02 to about 0.2,
α is from about 0.1 to about 0.4,
β is from about 0.35 to about 0.869,
γ is from about 0.01 to about 0.2,
δ is from 0.0 to about 0.1 and
z is from about 0.01 to about 0.2,
where A is Mg, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb or combinations thereof, and wherein
the electroactive composition exhibits a specific capacity of at least about 175 mAh/g when discharged from 4.6 volts to 2.0 volts at room temperature at the 10 th cycle at a rate of 1C.
2. The electroactive composition of claim 1 wherein x is in the range from about 0.05 to about 0.175.
3. The electroactive composition of claim 1 wherein α is in the range from about 0.15 to about 0.35.
4. The electroactive composition of claim 1 wherein β is in the range from about 0.35 to about 0.60.
5. The electroactive composition of claim 1 wherein γ is in the range from about 0.08 to about 0.2.
6. The electroactive composition of claim 1 wherein z is in the range from about 0.01 to about 0.1.
7. The electroactive composition of claim 1 wherein z is in the range from about 0.01 to about 0.075.
8. The electroactive composition of claim 1 wherein the sum x+α+β+γ+δ is approximately equal to 1.
9. The electroactive composition of claim 8 wherein the composition has a layer layer structure represented by a Li 2 MO 3 .(1−a) LiM'O 2 .
10. A battery comprising a positive electrode comprising a composition of claim 1 , a negative electrode comprising a lithium intercalation alloy material and an electrolyte comprising lithium cations.
11. A method for synthesizing the electroactive composition of claim 1 , the method comprising heating a fluorine source in contact with a metal oxide approximately represented by a formula Lil+xNiαMnβCoγAδO2 where x ranges from about 0.02 to about 0.2, α ranges from about 0.1 to about 0.4, β range from about 0.35 to about 0.869, γ ranges from about 0.01 to about 0.2, and δ ranges from about 0 to about 0.1, and where A is Mg, Zn, A1, Ga, B, Zr, Ti, Ca, Ce, Y, Nb or combinations thereof, at a temperature from about 150° C. to about 700° C. for at least about 10 minutes to form the electroactive composition.
12. The method of claim 11 wherein the fluorine source comprises NH 4 HF 2 .
13. The method of claim 11 wherein the heating is performed at a temperature from about 350° C. to about 500° C.
14. The method of claim 11 wherein the heating is performed for about 2 hours to about 10 hours.
15. The method of claim 11 wherein the fluorine source and the metal oxide composition are blended as powders prior to the heating step.
16. The method of claim 11 wherein x is from about 0.05 to about 0.175, α is from about 0.15 to about 0.35, β is from about 0.35 to about 0.70, γ is from about 0.05 to about 0.2, and z is from about 0.01 to about 0.075.
17. The method of claim 11 wherein the sum x+α+β+γ+δ is approximately equal to 1.
18. An electroactive composition synthesized according to the method of claim 16 .
19. A secondary lithium ion battery comprising a positive electrode, a negative electrode comprising a lithium intercalation/alloy composition, a separator between the positive electrode and the negative electrode and a non-aqueous electrolyte comprising lithium ions, wherein the positive electrode comprises the electroactive composition of claim 1 that exhibits a specific capacity of at least about 180 mAh/g when discharged from 4.6 volts to 2.0 volts at room temperature at the 10th cycle at a rate of 1C.
20. The secondary lithium ion battery of claim 19 wherein x is from about 0.05 to about 0.175, α is from about 0.15 to about 0.35, β is from about 0.35 to about 0.70, γ is from about 0.05 to about 0.2, δ is from 0.0 to about 0.1 and z is from about 0.01 to about 0.075.
21. The secondary lithium ion battery of claim 19 wherein the negative electrode comprises graphitic carbon.
22. A secondary lithium ion battery comprising a positive electrode, a negative electrode comprising a lithium intercalation alloy composition, a separator between the positive electrode and the negative electrode and a non-aqueous electrolyte comprising lithium ions, wherein the positive electrode comprises the electroactive compositions of claim 1 that exhibits a specific capacity of at least about 100 mAh g when discharged from 4.6 volts to 2.0 volts at room temperature at the 20th cycle at a rate of 5C.
23. The secondary lithium ion battery of claim 22 wherein x is from about 0.05 to about 0.175, α s from about 0.15 to about 0.35, β is from about 0.35 to about 0.70, γ is from about 0.05 to about 0.2, δ is from 0.0 to about 0.1 and z is from about 0.01 to about 0.075.
24. The secondary lithium ion battery of claim 22 wherein the negative electrode comprises graphitic carbon.