Substituted phenothiazine redox shuttles for rechargeable lithium-ion cell

• US 20060263697A1
• Filed: 05/17/2005
• Published: 11/23/2006
• Est. Priority Date: 05/17/2005
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Lamanna, William M., Dahn, Jeffrey R., Buhrmester, Claudia, Wang, Richard L.
• Granted Patent: US 7,615,312 B2
• Time in Patent Office: Days
• US Class Current: 429/336
• 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 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• CPC Class Codes: H01M 2300/0042 Four or more solvents
• 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 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/136 Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• 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 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/49108 Electric battery cell making
• CPC Class Codes: Y10T 29/4911 including sealing

Abstract

A rechargeable lithium-ion cell contains a positive electrode, negative electrode, charge-carrying electrolyte containing charge carrying medium and lithium salt, and an N-substituted or C-substituted phenothiazine compound dissolved in or dissolvable in the electrolyte. The substituted phenothiazine compound has an oxidation potential above the positive electrode recharged potential and serves as a cyclable redox chemical shuttle providing cell overcharge protection.

Claims

1. A rechargeable lithium-ion cell comprising:

(a) a positive electrode having a recharged potential;

(b) a negative electrode;

(c) a charge-carrying electrolyte comprising a charge carrying medium and a lithium salt; and

(d) a cyclable redox chemical shuttle comprising an N-substituted or C-substituted phenothiazine compound dissolved in or dissolvable in the electrolyte and having an oxidation potential above the recharged potential of the positive electrode.

2. A cell according to claim 1 wherein the phenothiazine compound is substituted at its nitrogen atom.

3. A cell according to claim 1 wherein the phenothiazine compound is substituted at one or more ring carbon atoms.

4. A cell according to claim 1 wherein the phenothiazine compound is substituted with one or more alkyl groups containing 1 to about 4 carbon atoms.

5. A cell according to claim 1 wherein the phenothiazine compound is substituted with one or more acyl, acyloxy, alkaryl, alkoxy, acetamido, amido, amino, aryl, aralkyl, alkyl carboxyl, aryl carboxyl, alkylsulfonyl, benzoyl, carbamoyl, carbamido, carboxy, cyano, formyl, halo, haloacetamido, haloacyl, haloalkylsulfonyl, haloaryl, hydroxyl, isothiocyanato, methylsulfonyloxyl, nitro, oxo, oxybenzoyl or phosphenoxy groups or combination thereof.

6. A cell according to claim 1 wherein the phenothiazine compound comprises 10-methyl-phenothiazine, 10-ethyl-phenothiazine, 3-chloro-10-ethyl-phenothiazine, 10-isopropyl-phenothiazine or 10-acetyl-phenothiazine or mixture thereof.

7. A cell according to claim 1 wherein the phenothiazine compound comprises 2-perfluoromethyl-phenothiazine, 2-chloro-10-methyl-phenothiazine, 2-ethyl-10-methyl-phenothiazine, 3-bromo-10-ethyl-phenothiazine, 3-chloro-10-methyl-phenothiazine, 3-iodo-10-methyl-phenothiazine, 10-methyl-phenothiazin-3-ol, 10-methyl-phenothiazin-3-ylamine, 2,10-dimethyl-phenothiazine, 3,10-dimethyl-phenothiazine, 3-methyl-10-ethyl-phenothiazine, 4,10-dimethyl-phenothiazine, 3,7,10-trimethyl-phenothiazine, 10-(2-chloroethyl)-phenothiazine, 10-formyl-phenothiazine, 10-methoxy-phenothiazine, 10-methoxymethyl-phenothiazine, 10-phenyl-phenothiazine, 10-propionyl-phenothiazine, 10-methyl-phenothiazine-4-carboxylic acid or mixture thereof.

8. A cell according to claim 1 wherein the phenothiazine compound comprises 2-cyano-10-perfluoromethylsulfonyl-phenothiazine, 2-methoxy-10-perfluoromethylsulfonyl-phenothiazine, 2-perfluoromethyl-10-perfluoromethylsulfonyl-phenothiazine, 10-perfluoromethyl-phenothiazine, 10-perfluoromethylsulfonyl-phenothiazine, 10-(1,1,1,2,3,3)-hexafluoropropyl-phenothiazine or mixture thereof.

9. A cell according to claim 1 wherein the phenothiazine compound is dissolved in the electrolyte.

10. A cell according to claim 9 wherein the electrolyte comprises a cosolvent.

11. A cell according to claim 1 wherein the phenothiazine compound has an oxidation potential from about 0.3 V to about 5 V above the recharged potential of the positive electrode.

12. A cell according to claim 1 wherein the phenothiazine compound has an oxidation potential from about 0.3 to about 0.6 V above the recharged potential of the positive electrode.

13. A cell according to claim 1 wherein the phenothiazine compound provides overcharge protection after at least 30 charge-discharge cycles at a charging voltage sufficient to oxidize the phenothiazine compound and at an overcharge charge flow equivalent to 100% of the cell capacity during each cycle.

14. A cell according to claim 1 wherein the phenothiazine compound provides overcharge protection after at least 80 charge-discharge cycles at a charging voltage sufficient to oxidize the phenothiazine compound and at an overcharge charge flow equivalent to 100% of the cell capacity during each cycle.

15. A cell according to claim 1 wherein the positive electrode comprises LiFePO₄, Li₂FeSiO₄, Li_xMnO₂ (where x is about 0.3 to about 0.4) or MnO₂.

16. A cell according to claim 1 wherein the negative electrode comprises graphitic carbon, lithium metal or a lithium alloy.

17. A cell according to claim 1 wherein the charge carrying medium comprises ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate or combination thereof.

18. A rechargeable lithium-ion cell comprising:

(a) a positive electrode having a recharged potential and comprising LiFePO₄, Li₂FeSiO₄, Li_xMnO₂ (where x is about 0.3 to about 0.4) or MnO₂;

(b) a negative electrode comprising graphitic carbon, lithium metal or a lithium alloy; and

(c) a charge-carrying electrolyte comprising;

(i) a charge-carrying media comprising ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate or combination thereof;

(ii) a lithium salt comprising LiPF₆, lithium bis(oxalato)borate or combination thereof; and

(iii) a cyclable redox chemical shuttle comprising 10-methyl-phenothiazine, 10-ethyl-phenothiazine, 3-chloro-10-ethyl-phenothiazine or 10-acetyl-phenothiazine or mixture thereof dissolved in the electrolyte and having an oxidation potential above the recharged potential of the positive electrode.

19. A method for manufacturing a rechargeable lithium-ion sealed cell comprising the steps of assembling in any order and enclosing in a suitable case:

(a) a positive electrode having a recharged potential;

(b) a negative electrode;

(c) a charge-carrying electrolyte comprising charge carrying medium and lithium salt; and

(d) a cyclable redox chemical shuttle comprising an N-substituted or C-substituted phenothiazine compound dissolved in or dissolvable in the electrolyte and having an oxidation potential above the recharged potential of the positive electrode.

20. A method for recharging a lithium-ion cell while chemically limiting cell damage due to overcharging comprising supplying charging current across a positive and a negative electrode of a lithium-ion rechargeable cell containing a charge-carrying electrolyte comprising a charge carrying medium, a lithium salt and a cyclable redox chemical shuttle comprising an N-substituted or C-substituted phenothiazine compound dissolved in the electrolyte and having an oxidation potential above the recharged potential of the positive electrode.