Cation-Substituted Spinel Oxide and Oxyfluoride Cathodes for Lithium Ion Batteries

• US 20080157027A1
• Filed: 09/25/2007
• Published: 07/03/2008
• Est. Priority Date: 09/25/2006
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Choi, Wonchang, Manthiram, Arumugam
• Granted Patent: US 7,718,319 B2
• Time in Patent Office: Days
• US Class Current: 252/506
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/1391 of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/362 Composites
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention includes compositions and methods of making cation-substituted and fluorine-substituted spinel cathode compositions by firing a LiMn_2-y-zLi_yM_zO₄ oxide with NH₄HF₂ at low temperatures of between about 300 and 700° C. for 2 to 8 hours and a η of more than 0 and less than about 0.50, mixed two-phase compositions consisting of a spinel cathode and a layered oxide cathode, and coupling them with unmodified or surface modified graphite anodes in lithium ion cells.

Claims

1. A method of making an oxyfluoride composition comprising the step of:

heating a composition having the formula LiMn<sub>2−

y−

z</sub>Li_yM_zO₄ in the presence of a fluoride source at a temperature within the range of about 200 to about 700°

C. for 2 to 8 hours to form a cation-substituted, fluorine-substituted LiMn<sub>2−

y−

z</sub>Li_yM_zO<sub>4−

η</sub>

F_η

spinel oxide structure, wherein y is within the range of about 0 to about 0.3, wherein z is within the range of about 0 to about 1.0, and wherein η

is greater than 0 and less than about 0.50.

2. The method of claim 1, wherein M is selected from the group consisting of Mg, Al, V, Cr, Fe, Ti, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ga, Sn and combinations thereof.

3. The method of claim 1, wherein the fluoride source comprises NH₄HF₂.

4. The method of claim 1, wherein y is within the range of about 0 to about 0.3, z is within the range of about 0 to about 1.0, and η

is within the range of about 0.05 to about 0.25.

5. The method of claim 1, wherein the composition is heated to a temperature within the range of about 425 to about 500°

C.

6. The method of claim 1, wherein the cation-substituted fluorine-substituted LiMn₂₋

y−

zLi_yM_zO<sub>4−

η</sub>

F_η

spinel oxide structure is selected from the group consisting of LiMn_1.8Li_0.2O_3.88F_0.12, LiMn_1.8Li_0.2O_3.79F_0.21, LiMn_1.8Li_0.1Ti_0.1O₄, LiMn_1.8Li_0.1Ti_0.1O_3.9F_0.1, LiMn_1.8Li_0.1Cu_0.1O₄, LiMn_1.8Li_0.1Cu_0.1O_3.9F_0.1, LiMn_1.8Li_0.1Ni_0.1O₄, LiMn_1.8Li_0.1Ni_0.1O_3.9F_0.1, and LiMn_1.8Li_0.1Ni_0.1O_3.8F_0.2.

7. The method of claim 1, wherein the cation-substituted, fluorine-substituted LiMn₂₋

y−

zLi_yM_zO<sub>4−

η</sub>

F_η

spinel oxide structure, when incorporated in a lithium-ion battery, has a capacity greater than about 80 mAh/g.

8. A composition comprising a cation-substituted, fluorine-substituted LiMn₂₋

y−

zLi_yM_zO<sub>4−

η</sub>

F_η

spinel oxide structure with fluorine incorporated into the spinel lattice, wherein η

is greater than 0 and is less than about 0.50.

9. The composition of claim 8, wherein the cation-substituted fluorine-substituted LiMn₂₋

y−

zLi_yM_zO<sub>4−

η</sub>

F_η

spinel oxide structure is selected from the group consisting of LiMn_1.8Li_0.2O_3.88F_0.12, LiMn_1.8Li_0.2O_3.79F_0.21, LiMn_1.8Li_0.1Ti_0.1O₄, LiMn_1.8Li_0.1Ti_0.1O_3.9F_0.1, LiMn_1.8Li_0.1Cu_0.1O₄, LiMn_1.8Li_0.1Cu_0.1O_3.9F_0.1, LiMn_1.8Li_0.1Ni_0.1O₄, LiMn_1.8Li_0.1Ni_0.1O_3.9F_0.1, and LiMn_1.8Li_0.1Ni_0.1O_3.8F_0.2.

10. A method of making a cathode comprising the steps of:

mixing a LiMn<sub>2−

y−

z</sub>Li_yM_zO<sub>4−

η</sub>

F_η

composition with a conductive diluent and a binder to form a cation-substituted, fluorine-substituted LiMn<sub>2−

y−

z</sub>Li_yM_zO<sub>4−

η</sub>

F_η

composition; and

forming the cation-substituted, fluorine-substituted LiMn<sub>2−

y−

z</sub>Li_yM_zO<sub>4−

η</sub>

F_η

composition into a cathode.

11. The method of claim 10, wherein the cathode is essentially cylindrical or essentially disk shaped.

12. The method of claim 10, wherein the binder comprises powdered polytetrafluoroethylene or polyvinylidene fluoride, and wherein the conductive diluent comprises acetylene black, carbon black, graphite, nickel powder, aluminum powder, titanium powder, or stainless steel powder.

13. The method of claim 10, wherein M is selected from the group consisting of Mg, Al, V, Cr, Fe, Ti, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ga, Sn, and combinations thereof.

14. The method of claim 10, wherein the LiMn₂₋

y−

zLi_yM_zO<sub>4−

η</sub>

F_η

composition is heated in air at a temperature within the range of about 400 to about 500°

C. for 2 to 8 hours.

15. The method of claim 11, further comprising cutting the cation-substituted, fluorine-substituted LiMn₂₋

y−

zLi_yM_zO<sub>4−

η</sub>

F_η

composition into circular electrodes having an area within the range of about 0.30 cm² to about 0.90 cm².

16. A cathode, comprising:

a LiMn<sub>2−

y−

z</sub>Li_yM_zO<sub>4−

η</sub>

F_η

cation-substituted spinel oxide material, wherein y comprises between about 0 and 0.3, z comprises between about 0 and 1.0 and η

comprises greater than 0 and less than about 0.5 in contact with a layered oxide material comprising Li[Ni,Mn,Co,Li]O₂ or a combination thereof.

17. The cathode of claim 16, wherein M is selected from the group consisting of Mg, Al, V, Cr, Fe, Ti, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ga, Sn and combinations thereof.

18. The cathode of claim 16, wherein the cation-substituted spinel oxide material is between about 20 wt % and 95 wt % and the layered oxide material is between about 80 wt % and 5 wt %.

19. The cathode of claim 16, wherein the LiMn₂₋

y−

zLi_yM_zO<sub>4−

η</sub>

F_η

cation-substituted spinel oxide material comprises from about 70 wt % to about 80 wt % LiMn_1.85Li_0.075Ni_0.04Al_0.035O₄, LiMn_1.8Li_0.1Ni_0.1O_3.8F_0.2, LiMn_1.8Li_0.1Ni_0.1O_3.8F_0.2, or a combination thereof, and wherein the layered oxide material comprises from about 20 wt % to about 30 wt % LiCoO₂, LiNi_0.5Mn_0.5O₂, or a combination thereof

20. The cathode of claim 16, wherein the carbon anode surface comprising TiO₂ or a spinel Li₄Ti₅O₁₂ coating.

21. A method of making a spinel and layered oxide cathode, comprising:

forming a cathode from a mixture of a cation-substituted spinel oxide material and a layered oxide material.

22. The method of claim 21, wherein the cation-substituted spinel oxide material comprises LiCoO₂.

23. The method of claim 21, wherein the cation-substituted spinel oxide material comprises LiMn₂₋

y−

zLi_yM_zO<sub>4−

η</sub>

F_η

.

24. The cathode of claim 21, wherein M is selected from the group consisting of Mg, Al, V, Cr, Fe, Ti, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ga, Sn, and combinations thereof.

25. The method of claim 21, wherein the cathode comprises about 60 wt % to about 90 wt % of the mixture of the cation-substituted spinel oxide material, and about 40 wt % to about 10 wt % of the layered oxide material.