Method for synthesizing nickel-cobalt-aluminum electrodes
Compositions and methods of preparing energy storage device electrode active materials and electrodes are described. A two-step synthesis process may be utilized to prepare single crystal electrode active materials and electrodes, such as a single crystal nickel-cobalt-aluminum material. In some embodiments, the two step synthesis process includes a first and a second lithiation step.
1. A method of preparing an electrode comprising:
a first lithiation step, wherein a first lithium component and an other metal component are present in a first lithium/other metal molar ratio of less than 1.0 and are sintered at a temperature between 800 and 950° C. for a time period between 1 and 24 hours to obtain a first lithiated material;
a second lithiation step, wherein the first lithiated material is sintered with an additional lithium component at between 650° C. and 760° C. for a time period between 1 and 24 hours to obtain a second lithiated material with a total lithium/other metal molar ratio; and
forming a lithium transition metal oxide electrode from the second lithiated material;
wherein the second lithiated material comprises a substantially impurity-free single crystal lithiated material.
2. The method of claim 1 , wherein the first lithiated material comprises a product having the formula Li (i-x) [Ni 0.88 Co 0.09 Al 0.03 ] (1+x) O 2 .
3. The method of claim 1 , wherein the first lithium/other metal molar ratio is about 0.6.
4. The method of claim 1 , wherein the first lithium/other metal molar ratio is about 0.7.
5. The method of claim 1 , wherein the first lithium/other metal molar ratio is about 0.8.
6. The method of claim 1 , wherein the first lithium/other metal molar ratio is about 0.9.
7. The method of claim 1 , wherein the first lithium/other metal molar ratio is about 0.95.
8. The method of claim 1 , wherein the first lithium/other metal molar ratio is about 0.975.
9. The method of claim 1 , wherein during the second lithiation step is performed for approximately 12 hours.
10. The method of claim 1 , wherein the total lithium/other metal molar ratio is between 1.0 and 1.03.
11. The method of claim 1 , wherein the other metal component comprises an element selected from the group consisting of Ni, Co, Al, Mn, Mg, and combinations thereof.
12. The method of claim 1 , wherein the other metal component comprises Ni, Co, and Al.
13. The method of claim 1 , wherein the other metal component comprises Ni and Al.
14. The method of claim 1 , further comprising forming a rechargeable battery from the lithium electrode.
15. The method of claim 1 , wherein first lithium component is LiOH.H 2 O.
16. The method of claim 1 , wherein the additional lithium component is LiOH.H 2 O.
17. The method of claim 1 , wherein the other metal component comprises a lithium nickel cobalt aluminum oxide (NCA) precursor, a lithium nickel manganese cobalt oxide (NMC) precursor, or a combination thereof.
18. The method of claim 17 , wherein the other metal component is NCA(OH) 2 having the formula Ni 1-x-y Co x Al y (OH) 2 .
19. The method of claim 1 , wherein the first lithium/other metal molar ratio is about 0.6-0.975.