Lithium ion battery with high voltage electrolytes and additives
View Patent ↗Desirable electrolyte compositions are described that are suitable for high voltage lithium ion batteries with a rated charge voltage at least about 4.45 volts. The electrolyte compositions can comprise ethylene carbonate and solvent composition selected from the group consisting of dimethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, γ-valerolactone or a combination thereof. The electrolyte can further comprise a stabilization additive. The electrolytes can be effectively used with lithium rich positive electrode active materials.
1. A high voltage lithium secondary battery comprising a positive electrode, a negative electrode, an electrolyte and a separator between the negative electrode and the positive electrode, wherein the negative electrode comprises a lithium intercalation/alloying compound and the positive electrode comprises a lithium intercalation material, the electrolyte comprising a primary lithium electrolyte salt, a solvent consisting essentially of ethylene carbonate and a liquid organic solvent selected from the group consisting of dimethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, γ-valerolactone or a combination thereof, and a lithium salt electrolyte stabilizing additive in a concentration from about 0.01 weight percent to about 10 weight percent,
wherein the lithium salt electrolyte stabilizing additive is represented by the formula:
where b is the charge of the anion, m is a number from 1 to 4, n is a number from 1 to 8, q is 0 or 1, M is Al, B, P, As, Sb, or Si, R 1 is a C 1 -C 10 alkylene group, C 4 -C 20 arylene group, halogenated forms of these groups, optionally with other substituents and/or heteroatoms and/or form rings, R 2 is a halogen or a C 1 -C 10 alkyl group, a C 4 -C 20 arylene group, halogenated forms of these groups, optionally with other substituents and/or heteroatoms and/or form rings, X 1 and X 2 are independently O, S or NR 4 , and R 4 is a halogen or an organic group.
2. The high voltage lithium secondary battery of claim 1 wherein the electrolyte comprises the lithium salt stabilizing additive in a concentration range from about 0.1 weight percent to about 5.0 weight percent.
3. The high voltage lithium secondary battery of claim 1 wherein M is boron.
4. The high voltage lithium secondary battery of claim 1 wherein the lithium salt electrolyte stabilizing additive is lithium difluoro oxalato borate.
5. The high voltage lithium secondary battery of claim 1 wherein the positive electrode lithium intercalation material comprises a lithium metal oxide 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 about 0.1 to about 0.4, βrange from about 0.3 to about 0.65, γranges from 0 to about 0.4, δranges from about 0 to about 0.15 and z ranges from 0 to about 0.2, 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.
6. The high voltage lithium ion secondary battery of claim 5 wherein the positive electrode lithium intercalation material has a coating.
7. The high voltage lithium secondary battery of claim 1 wherein the negative electrode lithium intercalation/alloying compound comprises elemental carbon.
8. The high voltage lithium secondary battery of claim 1 wherein the electrolyte has a solvent comprising ethylene carbonate and dimethylcarbonate with a volume ratio of ethylene carbonate to dimethylcarbonate from about 2:1 to about 1:4.
9. The high voltage lithium secondary battery of claim 1 wherein the battery has a cycle life with at least about 70% capacity at 120 cycles relative to cycle 5 at a C/3 discharge from 4,5V to 2.0V.
10. The high voltage lithium secondary battery of claim 1 wherein the positive electrode lithium intercalation material is approximately represented by the formula x Li 2 M′O 3 ·(1−x)LiMO 2 , where M represents one or more metal ions having an average valance of +3 and M′ represents one or more metal ions having an average valance of +4.
11. The high voltage lithium secondary battery of claim 10 wherein M′ comprises Mn and M comprises Mn, Co and Ni.
12. The high voltage lithium secondary battery of claim 1 wherein the primary lithium electrolyte salt comprises LiPF 6 and/or LiBF 4 .
13. The high voltage lithium secondary battery of claim 1 wherein the primary lithium electrolyte salt has a concentration from about 1.25M to about 2.5M.
14. The high voltage lithium secondary battery of claim 1 wherein the electrolyte is stable up to 4.45 volts.
15. The high voltage lithium ion secondary battery of claim 14 wherein the positive electrode active material has a specific discharge capacity of at least about 175 mAh/g at a discharge rate of C/3 at the 120 th discharge cycle at room temperature when discharged between 4.5 volts to 2.0 volts.
16. The high voltage lithium secondary battery of claim 14 wherein the battery has a cycle life with at least about 70% capacity at 120 cycles relative to cycle 5 at a C/3 discharge from 4.5V to 2.0V.
17. A high voltage lithium secondary battery comprising a positive electrode, a negative electrode, an electrolyte and a separator between the negative electrode and the positive electrode, wherein the negative electrode comprises a lithium intercalation/alloying compound and the positive electrode comprises a lithium intercalation material, the electrolyte comprising a primary lithium electrolyte salt, a solvent comprising ethylene carbonate and a liquid organic solvent selected from the group consisting of dimethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, γ-valerolactone or a combination thereof, and a lithium salt electrolyte stabilizing additive in a concentration from about 0.01 weight percent to about 10 weight percent,
wherein the lithium salt electrolyte stabilizing additive is represented by the formula:
where b is the charge of the anion, m is a number from 1 to 4, n is a number from 1 to 8, q is 0 or 1, M is Al, B, P, As, Sb or Si, R 1 is a C 1 -C 10 alkylene group, C 4 -C 20 arylene group, halogenated forms of these groups, optionally with other substituents and/or heteroatoms and/or form rings, R 2 is a halogen or a C 1 -C 10 alkyl group, a C 4 -C 20 arylene group, halogenated forms of these groups, optionally with other substituents and/or heteroatoms and/or form rings, X 1 and X 2 are independently O, S or NR 4 , and R 4 is a halogen or an organic group, and
wherein the primary lithium electrolyte salt has a concentration from about 1.25M to about 2.0M.
18. The high voltage lithium secondary battery of claim 17 wherein the primary lithium electrolyte salt comprises LiPF 6 and/or LiBF 4 in a concentration from about 1.25M to about 1.75M.
19. The high voltage lithium secondary battery of claim 17 wherein the electrolyte is stable up to 4.45 volts.
20. The high voltage lithium secondary battery of claim 17 wherein the electrolyte comprises the lithium salt stabilizing additive in a concentration ranging from about 0.1 weight percent to about 5.0 weight percent.
21. The high voltage lithium secondary battery of claim 17 wherein the lithium salt electrolyte stabilizing additive is lithium difluoro oxalato borate.
22. The high voltage lithium secondary battery of claim 17 wherein the solvent of the electrolyte comprises ethylene carbonate and dimethylcarbonate with a volume ratio of ethylene carbonate to dimethylcarbonate from about 2:1 to about 1:4.
23. The high voltage lithium secondary battery of claim 17 wherein the lithium metal oxide is approximately represented by the formula x Li 2 M′O 3 ·(1−x)LiMO 2 , where wherein M′ comprises Mn and M comprises Mn, Co and Ni.