Mixtures of lithium manganese oxide spinel as cathode active material

• US 6,159,636 A
• Filed: 03/01/1999
• Issued: 12/12/2000
• Est. Priority Date: 04/08/1996
• Status: Expired due to Term

• Current Assignee: Duracell U.S. Operations, Inc. (Berkshire Hathaway Incorporated)
• Original Assignee: Gillette Company (The Procter & Gamble Company)
• Inventors: Wang, Enoch I., Taylor, Alwyn H., Bowden, William L.
• Primary Examiner(s): WEINER, LAURA S
• Application Number:
  US09/260,157
• Time in Patent Office: 652 Days
• Field of Search: 429/231.1, 429/224, 429/223, 429/231.6, 429/221, 429/231.3
• US Class Current: 429/223
• CPC Class Codes: C01G 45/1221 Manganates or manganites with a manganese oxidation state of Mn(III), Mn(IV) or mixtures thereof
• CPC Class Codes: C01G 45/1228 of the type [MnO2]n- , e.g. LiMnO2, Li[MxMn1-x]O2
• CPC Class Codes: C01G 45/1242 of the type [Mn2O4]-, e.g. LiMn2O4, Li[MxMn2-x]O4
• CPC Class Codes: C01G 51/42 containing alkali metals, e.g. LiCoO2
• CPC Class Codes: C01G 53/42 containing alkali metals, e.g. LiNiO2
• CPC Class Codes: C01P 2002/32 spinel-type (AB2O4)
• CPC Class Codes: C01P 2002/54 one element only
• CPC Class Codes: C01P 2006/40 Electric properties
• 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 4/364 as mixtures
• CPC Class Codes: H01M 4/366 as layered products
• 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

A method of making lithium manganese oxide of spinel structure is disclosed. The method involves the step of prelithiating a manganese oxide by reacting it with lithium hydroxide or lithium salt and then reacting the prelithiated manganese oxide in a second step at elevated temperature, for example, with lithium carbonate to form a lithium manganese oxide spinel. The spinel product may be used advantageously in secondary (rechargeable) batteries. The spinel product may be admixed with a partially substituted nickelite, preferably, LiNi_x Co_1-x O₂ (0.1<x<0.9) or LiNi_x Mg_1-x O₂ (0.85<x<0.97) and mixtures thereof to form the active material for the positive electrode of a rechargeable lithium ion cell. A preferred mixture for the positive electrode of lithium ion cells comprises lithium manganese oxide spinel and LiNi_x Co_1-x O₂ (0.1<x<0.9). The positive electrode for lithium ion cells may also be formed of a layer comprising active material of lithium manganese oxide spinel overlayed with a second layer comprising active material formed of a partially substituted nickelite, preferably LiNi_x Co_1-x O₂ (0.1<x<0.9) or LiNi_x Mg_1-x O₂ (0.85<x<0.97) and mixtures thereof.

Claims

1. A rechargeable lithium ion cell comprising a positive electrode, a negative electrode and electrolyte, wherein the positive electrode comprises a conductive support, a first layer on said conductive support, said first layer comprising active material comprising lithium manganese oxide of spinel structure of formula Li_x Mn₂ O_4+d (0.9<

x<

1.2 and 0<

d<

0.4) and a second layer over said first layer, said second layer comprising active material comprising partially substituted nickelite selected from the group consisting of LiNi_x Co_1-x O₂ (0.1<

x<

0.9) and LiNi_x Mg_1-x O₂ (0.85<

x<

0.97) and mixtures thereof.

2. The lithium ion cell of claim 1 wherein the electrolyte is a liquid during the useful life of the cell.

3. The lithium ion cell of claim 1 wherein the electrolyte is a liquid comprising a lithium salt dissolved in an non-aqueous solvent.

4. The lithium ion cell of claim 1 wherein the electrolyte is a liquid comprising lithium hexafluorophosphate (LiPF₆) dissolved in a nonaqueous solvent.

5. The lithium ion cell of claim 1 wherein the electrolyte is a solid.

6. The lithium ion cell of claim 1 wherein the active material in said second layer comprises a lithium nickel cobalt oxide having the formula LiNi_x Co_1-x O₂ (0.1<

x<

0.9).

7. The lithium ion cell of claim 6 wherein said active material in said second layer comprises LiNi₀.8 Co₀.2 O₂.

8. The lithium ion cell of claim 1 wherein said active material in said first and second layer comprises between about 50 and 95 percent by weight of said first and second layer.

9. The lithium ion cell of claim 1 wherein said partially substituted nickelite comprises between about 10 and 50 percent by weight of said first and second layer.

10. The lithium ion cell of claim 1 wherein said partially substituted nickelite comprises between about 30 and 40 percent by weight of said second layer.

11. The lithium ion cell of claim 1 wherein the weight ratio of said partially substituted nickelite in said second layer to Li_x Mn₂ O_4+d spinel (0.9<

x<

1.2 and 0<

d<

0.4) in said first layer is between about 0.04 and 0.50.

12. The lithium ion cell of claim 1 comprising a separator between said negative and positive electrodes and wherein said second layer of the positive electrode contacts said first layer and the negative and positive electrodes are oriented so that said second layer is closer to said separator electrode than said first layer.