Overcharge protection of nonaqueous rechargeable lithium batteries by cyano-substituted thiophenes as electrolyte additives

• US 20040053138A1
• Filed: 09/12/2003
• Published: 03/18/2004
• Est. Priority Date: 09/16/2002
• Status: Abandoned Application

• Current Assignee: HC Starck GmbH (OPUS Investment SARL)
• Original Assignee: HC Starck GmbH (OPUS Investment SARL)
• Inventors: Otterstedt, Ralph, Kirchmeyer, Stephan, Brassat, Lutz
• Application Number:
  US10/660,846
• Publication Number:
  US 20040053138A1
• Time in Patent Office: Days
• US Class Current: 429/307
• 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 10/0565 Polymeric materials, e.g. gel-type or solid-type
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0587 of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
• 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 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• 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
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The invention relates to the use of cyano-substituted thiophenes as electrolyte additives for protecting nonaqueous, rechargeable lithium batteries from overcharging, and lithium batteries comprising these additives.

Claims

1. Rechargeable lithium battery having a maximum permissible cell voltage for use in the intended manner, comprising

an anode comprising a material which is capable of incorporating lithium ions and releasing them again,

a cathode comprising a material which is capable of releasing lithium ions and incorporating them again,

a separator,

a nonaqueous electrolyte comprising one or more solvents and one or more conductive salts optionally embedded in a polymeric gel matrix,

characterized in that the nonaqueous electrolyte additionally comprises a thiophene of the general formula (I)

in which

R¹ to R⁴, independently of one another, are H, C₁-C₁₈-alkyl, C₁-C₁₈haloalkyl, C₁-C_{1 8}-alkoxy, C₁-C₁₈-haloalkoxy, halogen or pseudohalogen, with the proviso that at least one of the radicals R¹ to R⁴ is CN.

2. Rechargeable lithium battery according to claim 1, characterized in that R¹ to R⁴, independently of one another, are H, C₁-C₆-alkyl, C₁-C₆-fluoroalkyl, C₁-C₆-alkoxy, C₁-C₆-fluoroalkoxy, F, Cl or CN, with the proviso that at least one of the radicals R¹ to R⁴ is CN.

3. Rechargeable lithium battery according to claim 1, characterized in that R¹ to R⁴, independently of one another, are H, with the proviso that at least one of the radicals R¹ to R⁴ is CN.

4. Rechargeable lithium battery according to claim 1, characterized in that the nonaqueous electrolyte comprises a thiophene of the general formula (I) in an amount of from 0.01 to 10% by volume.

5. Rechargeable lithium battery according to claim 1, characterized in that the nonaqueous electrolyte comprises a thiophene of the general formula (I) in an amount of from 2 to 5% by volume.

6. Rechargeable lithium battery according to claim 1, characterized in that the anode comprises

metallic lithium or

alloys containing metallic lithium or

carbon-like optionally graphitic or non-graphitic materials or

carbon-based materials which contain further nonmetallic components in addition to carbon, or

ternary compounds of boron, carbon and nitrogen or

oxides or sulphides of main group and subgroup elements.

7. Rechargeable lithium battery according to claim 1, characterized in that the cathode comprises one or more transition metal chalcogenides or one or more mixed oxides of lithium and one or more transition metals and/or main group metals.

8. Rechargeable lithium battery according to claim 1, characterized in that the cathode comprises LiNi₁₋

xCo_xO₂, LiNi<sub>1−

x−

y</sub>Co_xAl_yO₂ or LiNi<sub>1−

x−

z</sub>Co_xMn_zO₂,

in which

x is a number from 0.05 to 0.5,

y is a number from 0 to 0.3 and

z is a number from 0 to 0.5,

or mixtures of these with one another or mixtures of these with other mixed oxides of lithium with transition metals and/or main group metals.

9. Rechargeable lithium battery according to claim 1, characterized in that the separator is a porous polymer membrane or porous glass.

10. Rechargeable lithium battery according to claim 1, characterized in that the nonaqueous electrolyte comprises one or more solvents selected from the group of the esters of carbonic acid, esters or nitriles of carboxylic acids, lactones, ethers, alkanes, and perfluorinated alkanes, and one or more conductive salt(s) selected from LiBF₄, LiPF₆, LiAsF₆, LiClO₄, lithium salts of perfluorinated carboxylic acids and perfluorinated alkanesulphonic or arylsulphonic acids, lithium-bisfluoroalkylsulphonyl-imides, lithium-trisfluoroalkylsulphonylmethides, lithium fluoroalkyl-phosphates, lithium bis(oxalato)borates, and lithium bis((salicylato)borates) optionally embedded in a polymeric gel matrix.

11. Rechargeable lithium battery according to claim 1, characterized in that the nonaqueous electrolyte comprises, as a solvent, ethylene carbonate, propylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate or vinylene carbonate or a mixture of at least two of these carbonic esters.

12. Rechargeable lithium battery according to claim 1, characterized in that the maximum permissible cell voltage for use in the intended manner is 4 V or higher.

13. A process for protecting rechargeable lithium batteries having a maximum permissible cell voltage for use in the intended manner from overcharging comprising adding thiophenes of the general formula (I)

14. The process according to claim 13, characterized by the rechargeable lithium batteries having a maximum permissible cell voltage of 4 V or higher for use in the intended manner.

15. Method for preventing the overcharging of rechargeable lithium batteries having a maximum permissible cell voltage for use in the intended manner, comprising an anode substantially comprising a material which is capable of incorporating lithium ions and releasing them again,

an anode comprising a material which is capable of incorporating lithium ions and releasing them again,

a cathode comprising a material which is capable of releasing lithium ions and incorporating them again,

a separator,

a nonaqueous electrolyte comprising one or more solvents and one or more conductive salts optionally embedded in a polymeric gel matrix,

comprising adding a thiophene of the general formula (I)

in which

R¹ to R⁴ have the meaning mentioned in claim 1,

to the nonaqueous electrolyte, which thiophene undergoes a chemical reaction at a voltage which is greater than the maximum permissible cell voltage of the battery for use in the intended manner, with the result that overcharging of the battery is counteracted.

16. Method according to claim 15, characterized in that the thiophene of the general formula (I) is added to the electrolyte in an amount of from 0.01 to 10% by volume.

17. Method according to claim 15, characterized in that the thiophene of the general formula (I) is added to the electrolyte in an amount of from 2 to 5% by volume.

18. Method according to claim 15, characterized in that the maximum permissible cell voltage of the battery for use in the intended manner is 4 V or higher.

19. Method according to claim 15, characterized in that the voltage at which the thiophene of the general formula (I) undergoes chemical reaction is 4.7 V or higher.