Very long cycling of lithium ion batteries with lithium rich cathode materials
View Patent ↗Lithium ion batteries can be activated and then cycled to exploit a moderate fraction of the discharge cycling capacity such that the discharge capacity and average discharge voltage stay within initial values for thousands of cycles. The superior cycling performance has been achieved at relatively high discharge rates and for practical battery formats. Lithium ion battery performance can also be achieved with superior cycling performance with partially activated batteries such that good discharge capacities can be exploited for many thousands of cycles before the discharge capacity and average discharge voltage drops more than 20% from initial values. The positive electrode active material can be a lithium rich metal oxide. The activation of the battery can comprise phase changes of the active materials. As described herein, the phase changes can be manipulated to exploit a reasonable fraction of the available high capacity of the material while providing outstanding cycling stability.
1. A lithium ion battery comprising:
a positive electrode comprising a lithium rich metal oxide composition;
a negative electrode comprising a lithium intercalation/alloying composition;
a non-aqueous electrolyte comprising lithium ions;
a separator between the negative electrode and the positive electrode; and
wherein the battery has been cycled through a formation cycle and wherein at the 500th cycle, the battery has a specific discharge capacity based on the mass of the positive electrode active composition of at least about 100 mAh/g at a discharge rate of C/3 from 4.25V to 2.0V that is at least about 90% of the 5th cycle specific discharge capacity and an average discharge voltage at a discharge rate of C/3 that is at least about 87.5% of the 5 th cycle average discharge voltage.
2. The lithium ion battery of claim 1 wherein the battery has been charged to a voltage upper limit from about 4.225 V to 4.45V during the formation cycle.
3. The lithium ion battery of claim 1 wherein the battery has been charged to a voltage upper limit from about 4.25 V to 4.375V during the formation cycle.
4. The lithium ion battery of claim 1 wherein the lithium metal oxide can be approximately represented by a formula Li 1+a Ni α Mn β Co γ A δ O 2-z F z , where a ranges from about 0.05 to about 0.3, α ranges from 0 to about 0.4, β range from about 0.2 to about 0.65, γ ranges from 0 to about 0.46, δ ranges from about 0 to about 0.15, z ranges from 0 to about 0.2 with the proviso that both α and γ are not zero, and where A is Mg, Sr, Ba, Cd, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb, Cr, Fe, V, Li, or combinations thereof.
5. The lithium ion battery of claim 1 wherein the lithium metal oxide can be approximately represented by the formula xLi 2 MnO 3 .(1−x)LiNi u Mn v Co w A y O 2 , where 0.03≦x≦0.55, 0≦w≦1, 0≦u≦0.5, 0≦y≦0.1 and v≈u.
6. The battery of claim 5 wherein x is between about 0.2 and 0.5.
7. The battery of claim 1 wherein the lithium rich metal oxide is coated with a metal halide or an inert metal oxide.
8. The lithium ion battery of claim 1 wherein the negative electrode comprises a graphitic carbon active material.
9. The battery of claim 1 wherein the electrolyte comprises a stabilizing additive.
10. The battery of claim 1 wherein at the 500th cycle, the battery has a specific discharge capacity that is at least about 90% of the 5th cycle specific discharge capacity and an average discharge voltage at a discharge rate of C/3 that is at least about 90% of the 5 th cycle average discharge voltage.
11. The battery of claim 1 wherein at the 1000th cycle, the battery has a specific discharge capacity that is at least about 87.5% of the 5th cycle specific discharge capacity and an average discharge voltage at a discharge rate of 2C that is at least about 87.5% of the 5 th cycle average discharge voltage.
12. The battery of claim 1 wherein at the 2500th cycle, the battery has a specific discharge capacity that is at least about 85% of the 5th cycle specific discharge capacity and an average discharge voltage at a discharge rate of 2C that is at least about 85% of the 5 th cycle average discharge voltage.
13. A method for cycling a lithium ion battery having a negative electrode comprising a lithium intercalation/alloying composition and a positive electrode comprising a lithium rich metal oxide, the method comprising:
following an initial formation cycle, cycling the battery with a charge voltage from about 4V to about 4.35V at an average discharge rate from about C/5 to about 2C, wherein the capacity after 2000 cycles is at least about 80 percent of the capacity at the 5th cycle at the same average discharge rate and the average voltage after 2000 cycles is at least about 85 percent of the 5th cycle average voltage at the same average discharge rate wherein the battery has a specific discharge capacity at the 5th cycle of at least about 100 mAh/g.
14. The method of claim 13 wherein the lithium metal oxide can be approximately represented by a formula Li 1+a Ni α Mn β Co γ A δ O 2−z F z , where a ranges from about 0.05 to about 0.3, α ranges from 0 to about 0.4, β range from about 0.2 to about 0.65, γ ranges from 0 to about 0.46, δ ranges from about 0 to about 0.15, z ranges from 0 to about 0.2 with the proviso that both α and γ are not zero, and where A is Mg, Sr, Ba, Cd, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb, Cr, Fe, V, Li, or combinations thereof.
15. The lithium ion battery of claim 13 wherein the lithium metal oxide can be approximately represented by the formula xLi 2 MnO 3 .(1−x) Li Ni u Mn v Co w A y O 2 , where 0.03≦x≦0.55, 0≦w≦1, 0≦u≦0.5, 0≦y≦0.1 and v≈u.
16. The method of claim 15 wherein x is between about 0.2 and 0.5, wherein the lithium rich metal oxide is coated with a metal halide or an inert metal oxide, wherein the lithium ion battery comprises a negative electrode comprising a graphitic carbon active material, and wherein the electrolyte comprises a stabilizing additive.
17. The method of claim 13 wherein the initial formation cycle comprises charging the battery to a voltage value from 4.225V to about 4.45 V.
18. The method of claim 13 wherein the capacity after 2000 cycles is at least about 90 percent of the capacity at the 5th cycle at the same average discharge rate and the average voltage after 2000 cycles is at least about 90 percent of the 5th cycle average voltage at the same average discharge rate.
19. The method of claim 13 wherein the capacity after 2000 cycles is at least about 92.5 percent of the capacity at the 5th cycle at the same average discharge rate and the average voltage after 2000 cycles is at least about 92.5 percent of the 5th cycle average voltage at the same average discharge rate.
20. The method of claim 13 wherein the battery is charged to a voltage from about 4.25V to about 4.4V during cycling.
21. The method of claim 13 wherein the negative electrode after 2000 cycles comprises no more than about 1 weight percent manganese.
22. A method for cycling a lithium ion battery having negative electrode comprising a lithium intercalation/alloying composition and a positive electrode comprising a lithium rich metal oxide, the method comprising:
following an initial formation cycle, cycling the battery with a charge voltage from about 3.8 to about 4.25 at an average rate from about C/5 to about 2C, wherein the capacity after 2000 cycles is at least about 80 percent of the capacity at the 5th cycle at the same average rate and the average voltage after 2000 cycles is at least about 85 percent of the 5th cycle average voltage at the same average rate.
23. The method of claim 22 wherein the battery has a specific discharge capacity at the 5th cycle of at least about 125 mAh/g when cycled from the selected charge voltage to 2V.
24. The method of claim 22 wherein the lithium metal oxide can be approximately represented by a formula Li 1+a Ni α Mn β Co γ A δ O 2−z F z , where a ranges from about 0.05 to about 0.3, α ranges from 0 to about 0.4, β range from about 0.2 to about 0.65, γ ranges from 0 to about 0.46, δ ranges from about 0 to about 0.15, z ranges from 0 to about 0.2 with the proviso that both α and γ are not zero, and where A is Mg, Sr, Ba, Cd, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb, Cr, Fe, V, Li, or combinations thereof.
25. The method of claim 22 wherein the lithium metal oxide can be approximately represented by the formula xLi 2 MnO 3 .(1−x) Li Ni u Mn v Co w A y O 2 , where 0.03≦x≦0.55, 0≦w≦1, 0≦u≦0.5, 0≦y≦0.1 and v≈u.
26. The method of claim 25 wherein x is between about 0.1 and 0.4, wherein the lithium rich metal oxide is coated with a metal halide or an inert metal oxide, wherein the lithium ion battery comprises a negative electrode comprising a graphitic carbon active material, and wherein the electrolyte comprises a stabilizing additive.
27. The method of claim 22 wherein the initial formation cycle comprises charging the battery to a voltage value greater than about 4.45V.
28. The method of claim 22 wherein the capacity after 2000 cycles is at least about 85 percent of the capacity at the 5th cycle at the same average rate and the average voltage after 2000 cycles is at least about 96 percent of the 5th cycle average voltage at the same average rate.
29. The method of claim 22 wherein the negative electrode after 2000 cycles comprise no more than about 1 weight percent manganese.
30. A method for cycling a lithium ion battery having a positive electrode comprising a lithium rich metal oxide, the method comprising:
following an initial formation cycle, cycling the battery with a charge voltage from about 4.25 to about 4.375 at an average rate from about C/5 to about 2C, wherein the battery is discharged to a voltage of no more than about 2.9V at least once every 200 cycles and wherein the capacity after 2000 cycles is at least about 80 percent of the capacity at the 5th cycle at the same average rate and the average voltage after 2000 cycles is at least about 85 percent of the 5th cycle average voltage at the same average rate.
31. The method of claim 30 wherein the battery has a specific discharge capacity at the 5th cycle of at least about 125 mAh/g when cycled from the selected charge voltage to 2V.
32. The method of claim 30 wherein the lithium metal oxide can be approximately represented by a formula Li 1+a Ni α Mn β Co γ A δ O 2−z F z , where a ranges from about 0.05 to about 0.3, α ranges from 0 to about 0.4, β range from about 0.2 to about 0.65, γ ranges from 0 to about 0.46, δ ranges from about 0 to about 0.15, z ranges from 0 to about 0.2 with the proviso that both α and γ are not zero, and where A is Mg, Sr, Ba, Cd, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb, Cr, Fe, V, Li, or combinations thereof.
33. The method of claim 30 wherein the lithium metal oxide can be approximately represented by the formula xLi 2 MnO 3 .(1−x) LiNi u Mn v CowA y O 2 , where 0.03≦x≦0.55, 0≦w≦1, 0≦u≦0.5, 0≦y≦0.1 and v u.
34. The method of claim 33 wherein x is between about 0.1 and 0.4, wherein the lithium rich metal oxide is coated with a metal halide or an inert metal oxide, wherein the lithium ion battery comprises a negative electrode comprising a graphitic carbon active material, and wherein the electrolyte comprises a stabilizing additive.
35. The method of claim 30 wherein the initial formation cycle comprises charging the battery to a voltage value greater than about 4.45V.
36. The method of claim 30 wherein the capacity after 2000 cycles is at least about 85 percent of the capacity at the 5th cycle at the same average rate and the average voltage after 2000 cycles is at least about 96 percent of the 5th cycle average voltage at the same average rate.
37. The method of claim 30 wherein the battery is discharged to a voltage of no more than about 2.9V at least once every 150 cycles.