Composite compound with mixed crystalline structure

• US 8,052,897 B2
• Filed: 12/09/2008
• Issued: 11/08/2011
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: BYD Company Limited
• Original Assignee: BYD Company Limited
• Inventors: Yin, Xiaoli, Bai, Lu, Tian, Ye, Xi, Xiaobing, Cheng, Tangli
• Primary Examiner(s): NGUYEN, KHANH TUAN
• Application Number:
  US12/316,173
• Publication Number:
  US 20090220860A1
• Time in Patent Office: 1,064 Days
• Field of Search: 252/500, 252/182.1, 252/506, 252/510, 252/519.1, 252/519.15, 429/218.1, 429/224, 429/231.95, 429/232, 429/52, 429/220, 296/231
• US Class Current: 252/519.1
• CPC Class Codes: C01G 30/00 Compounds of antimony
• CPC Class Codes: C01G 31/00 Compounds of vanadium
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: H01B 1/08 oxides
• 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 10/0568 characterised by the solutes
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• 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: H01M 4/581 Chalcogenides or intercalation compounds thereof
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

A composite lithium compound having a mixed crystalline structure is provided. Such compound can be formed by heating lithium, iron, phosphorous and carbon sources with a lithium metal compound. The resulting mixed metal crystal can exhibit superior electrical property and is a better cathode material for lithium secondary batteries.

Claims

1. A cathode active material comprising a mixed crystal, the mixed crystal having:

a first crystalline substance having one or more members with the general formulas Li_xxM′

_yy(XO₄)_zz, LiM′

XO₅, LiM′

XO₆ and LiM′

X₂O₇, wherein;

0<

xx/zz≦

1 and 0<

yy/zz≦

1;

M′

is selected from elements Na, Mn, Fe, Co, Ni, Ti, Nb and V;

X is selected from elements P, S, As, Mo and W; and

a second crystalline substance having one or more members with the general formulas LiD_cO₂, Li_iNi_1-d-eCo_dMn_eO₂, LiNi_1-f-gCo_fAl_gO₂, Li_xNi_1-yCoO₂, Li_aM_bMn_2-bO₄ and Li_mMn_2-nE_nO_j, wherein;

D is selected from elements B, Mg, Al, Ti, Cr, Fe, Cu, Zn, Ga, Y, La and V;

0<

c≦

3, 0.9≦

i≦

1.2, 0≦

d≦

0.5, 0≦

e≦

0.3, 0≦

f≦

0.5, 0≦

g≦

0.3, 0.9≦

x≦

1.1 and 0≦

y≦

1;

M is selected from elements boron, magnesium, aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, gallium and yttrium;

0.9≦

a≦

1.2 and 0≦

b≦

1;

E includes one or more transition metals; and

0.9≦

m≦

1.1, 0≦

n≦

1 and 1<

j<

6,

wherein the first crystalline substance has a lattice, and at least a part of the second crystalline substance is received by and distributed in the lattice of the first crystalline structure.

2. The material of claim 1 having electrical conductivity of about 0.001 to 10 S/cm at about 25°

C.

3. The material of claim 1, wherein the first crystalline substance and the second crystalline substance has molar ratios of about 1 to 0.01-0.05, taking only the lithium components in the material into consideration.

4. The material of claim 1, wherein the first crystalline substance includes one or more members selected from the group consisting of LiFePO₄, LiMnPO₄, LiCoPO₄, Li₃Fe₂(PO₄)₃, LiTi₂(PO₄)₃, Li₃V₂(PO₄)₃, Li₂NaV₂(PO₄)₃, LiTiPO₅, LiVMoO₆, LiVWO₆, LiVP₂O₇ and LiFeAs₂O₇ and the second crystalline substance includes one or more members selected from the group consisting of LiCoO₂, LiNiO₂, LiMn₂O₄, LiVO₂, Li_1.03Ni_0.77Co_0.1Mn_0.1O₂, LiNi_0.8Co_0.15Al_0.05O₂ and LiMnBO₃.

5. The material of claim 1, further comprising a carbon additive, wherein the carbon additive is capable of providing the mixed crystal with about 1-5% of carbon by weight.

6. The material of claim 5, wherein the carbon additive includes one or more members selected from the group consisting of carbon black, acetylene black, graphite, glucose, sucrose, citric acid, starch, dextrin and polyethylene glycol.

7. A lithium ion secondary battery comprising a battery case, electrodes and electrolyte, the electrodes and electrolyte being sealed within the battery case, the electrodes having wounded or stacked cathode, anode and divider film, the cathode further comprising the cathode material of claim 1.

8. A cathode active material comprising a mixed crystal, the mixed crystal having:

a first crystalline substance having a combination of lithium, iron and phosphorous sources, wherein the lithium, iron and phosphorous (Li;

Fe;

P) sources have molar ratios of about 0.95-1.1;

1;

0.95-1.1; and

a second crystalline substance having one or more members with the general formulas LiD_cO₂, Li_iNi_1-d-eCo_dMn_eO₂, LiNi_1-f-gCo_fAl_gO₂, Li_xNi_1-yCoO₂, Li_aM_bMn_2-bO₄ and Li_mMn_2-nE_nO_j, wherein;

D is selected from elements B, Mg, Al, Ti, Cr, Fe, Cu, Zn, Ga, Y, La and V;

0<

c≦

3, 0.9≦

i≦

1.2, 0≦

d≦

0.5, 0≦

e≦

0.3, 0≦

f≦

0.5, 0≦

g≦

0.3, 0.9≦

x≦

1.1 and 0≦

y≦

1;

M is selected from elements boron, magnesium, aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, gallium and yttrium;

0.9≦

a≦

1.2 and 0≦

b≦

1;

E includes one or more transition metals; and

0.9≦

m≦

1.1, 0≦

n≦

1 and 1<

j<

6,

wherein the first crystalline substance has a lattice, and at least a part of the second crystalline substance is received by and distributed in the lattice of the first crystalline structure.

9. The material of claim 8 having electrical conductivity of about 0.001 to 10 S/cm at about 25°

C.

10. The material of claim 8, wherein the phosphorous source and the second crystalline substance has molar ratios of about 1 to 0.01-0.05, taking only the lithium components and phosphorous source in the material into consideration.

11. The material of claim 8, wherein the second crystalline substance includes one or more members selected from the group consisting of LiCoO₂, LiNiO₂, LiMn₂O₄, LiVO₂, Li_1.03Ni_0.77Co_0.1Mn_0.1O₂, LiNi_0.8Co_0.15Al_0.05O₂ and LiMnBO₃.

12. The material of claim 8, wherein the lithium source includes one or more members selected from the group consisting of lithium carbonate, lithium hydroxide, lithium oxalate and lithium acetate;

the iron source includes one or more members selected from the group consisting of ferrous oxalate, ferrous carbonate, iron acetate, iron oxide, iron phosphate, iron pyrophosphate and iron nitrate; and

the phosphate source includes one or more members selected from the group consisting of ammonium phosphate, ammonium dihydrogen phosphate, ammonium, iron phosphate, phosphoric acid and lithium dihydrogen phosphate.

13. The material of claim 8, further comprising a carbon additive, wherein the carbon additive is capable of providing the mixed crystal with about 1-5% of carbon by weight.

14. The material of claim 13, wherein the carbon additive includes one or more members selected from the group consisting of carbon black, acetylene black, graphite, glucose, sucrose, citric acid, starch, dextrin and polyethylene glycol.

15. A lithium ion secondary battery comprising a battery case, electrodes and electrolyte, the electrodes and electrolyte being sealed within the battery case, the electrodes having wounded or stacked cathode, anode and divider film, the cathode further comprising the cathode material of claim 8.

16. A cathode active material comprising a mixed crystal, the mixed crystal having:

a first crystalline substance having one or more members selected from the group consisting of LiFePO₄, LiMnPO₄, LiCoPO₄, Li₃Fe₂(PO₄)₃, LiTi₂(PO₄)₃, Li₃V₂(PO₄)₃, Li₂NaV₂(PO₄)₃, LiTiPO₅, LiVMoO₆, LiVWO₆, LiVP₂O₇ and LiFeAs₂O₇; and

a second crystalline substance includes one or more members selected from the group consisting of LiCoO₂, LiNiO₂, LiMn₂O₄, LiVO₂, Li_1.03Ni_0.77Co_0.1Mn_0.1O₂, LiNi_0.8Co_0.15Al_0.05O₂ and LiMnBO₃,

wherein the first crystalline substance has a lattice, and at least a part of the second crystalline substance is received by and distributed in the lattice of the first crystalline structure.

17. The material of claim 16 having electrical conductivity of about 0.001 to 10 S/cm at about 25°

C.

18. The material of claim 16, further comprising a carbon additive, wherein the carbon additive is capable of providing the mixed crystal with about 1-5% of carbon by weight.

19. The material of claim 18, wherein the carbon additive includes one or more members selected from the group consisting of carbon black, acetylene black, graphite, glucose, sucrose, citric acid, starch, dextrin and polyethylene glycol.

20. A lithium ion secondary battery comprising a battery case, electrodes and electrolyte, the electrodes and electrolyte being sealed within the battery case, the electrodes having wounded or stacked cathode, anode and divider film, the cathode further comprising the cathode material of claim 16.