Polymer electrolyte for a lithium sulfur cell

• US 10,601,031 B2
• Filed: 06/05/2015
• Issued: 03/24/2020
• Est. Priority Date: 06/06/2014
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Fanous, Jean, Schumann, Bernd, Thielen, Joerg
• Primary Examiner(s): Lee, Sin J
• Application Number:
  US15/316,063
• Publication Number:
  US 20170179468A1
• Time in Patent Office: 1,754 Days
• Field of Search: None
• CPC Class Codes: H01M 10/052 Li-accumulators
• 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 2004/028 Positive electrodes
• CPC Class Codes: H01M 2300/0082 Organic polymers
• 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 4/137 Electrodes based on electro-active polymers
• CPC Class Codes: H01M 4/362 Composites
• CPC Class Codes: H01M 4/5815 Sulfides
• CPC Class Codes: H01M 4/602 Polymers
• CPC Class Codes: H01M 4/622 being polymers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A polymer or a polymer electrolyte and cathode material for an alkali metal cell, in particular for a lithium-sulfur cell. To improve the performance and reliability of alkali metal cells, for example lithium-sulfur cells, a polymer based on the general chemical formula (I) is provided, where -[A]- stands for a unit which forms a polymer backbone, X stands for a spacer, x stands for the number of spacers X and is 1 or 0, Q stands for a positively charged group Q⁺ and a counterion Z⁻, or Q stands for a negatively charged group Q⁻ and a counterion Z⁺, or Q stands for an uncharged group. Moreover, the invention relates to the use thereof, and a cathode, a separator, a protective layer, and a cell.

Claims

1. A cathode material for an alkali metal cell, comprising:

at least one cathode active material containing sulfur;

at least one polymer electrolyte including at least one repeating unit of the general chemical formula;

2. The cathode material of claim 1, wherein

the at least one second repeating unit is an ethylene oxide unit and/or a repeating unit which bears an oligoethylene oxide function, and

the at least one second polymer is a polyethylene oxide and/or includes a repeating unit which bears an oligoethylene oxide function.

3. The cathode material of claim 1, wherein

Q⁻

stands for a group based on a lithium conducting salt anion or a group based on an anion of an ionic liquid, or a sulfonate group or a sulfate group or a carboxylate group or a group based on a phosphoric acid-based anion or a group based on an anion of an imide or a group based on an anion of an amide or a group based on an anion of a carboxylic acid amide, and Z⁺stands for a lithium ion, or

Q⁺stands for a group based on a cation of an ionic liquid and Z⁻

stands for a lithium conducting salt anion.

4. The cathode material of claim 1, wherein

Q⁻

stands for a trifluoromethanesulfonylimide group or perfluoroethanesulfonylimide group or fluorosulfonylimide group or a sulfonate group or a trifluoromethanesulfonate group, and Z⁺stands for a lithium ion, or

Q⁺stands for a pyridinium group or an ammonium group or an imidazolium group or a piperidinium group or a pyrrolidinium group or a phosphonium group or a guanidinium group or a morpholinium group or a uronium group or a thiouronium group, and Z⁻

stands for a lithium conducting salt anion.

5. The cathode material of claim 1, wherein

Z⁻

stands for bis(trifluoromethanesulfonyl)imide and/or bis(perfluoroethanesulfonyl)imide and/or bis(fluorosulfonyl)imide and/or trifluoromethanesulfonate and/or tetrafluoroborate and/or bisoxalatoborate and/or difluorooxalatoborate and/or bromide and/or iodide and/or chloride, or

Z⁺stands for a lithium ion.

6. The cathode material of claim 1, wherein the polymer backbone-forming unit -[A]- includes an alkylene oxide unit and/or a unit which includes a carbonate group, and/or a siloxane unit and/or a phosphazene unit and/or a methyl methacrylate unit and/or a methacrylate unit and/or a phenylene unit and/or a phenylene oxide unit and/or a benzylene unit and/or an alkylene unit.

7. The cathode material of claim 1, wherein the polymer backbone-forming unit -[A]- includes at least one polyfunctionalized siloxane unit and/or one polyfunctionalized phosphazene unit and/or one polyfunctionalized phenylene unit.

8. The cathode material of claim 1, wherein the spacer X includes at least one oligoalkylene oxide group.

9. The cathode material of claim 1, wherein the spacer X includes at least one carbonyl group and/or at least one lactone group and/or at least one cyclic carbamate group and/or at least one acyclic carbonate group and/or at least one acyclic carboxylic acid ester group and/or at least one acyclic carbamate group.

10. The cathode material of claim 1, wherein the spacer X includes:

at least one other negatively charged group Q⁻

that includes at least one sulfonylimide group and/or a sulfonate group, and a counterion Z⁺;

or

at least one other positively charged group Q⁺that includes at least one ammonium ion group and/or at least one pyridinium group and/or at least one imidazolium group and/or at least one piperidinium group and/or at least one pyrrolidinium group and/or at least one phosphonium group and/or at least one guanidinium group and/or at least one morpholinium group and/or at least one uronium group and/or at least one thiouronium group, and a counterion Z⁻

.

11. The cathode material of claim 1, wherein the polymer backbone-forming unit -[A]- and/or the spacer X and/or the group Q or Q⁺or Q⁻

are/is fluorinated.

12. The cathode material of claim 1, wherein the polymer backbone-forming unit -[A]- and/or the spacer X and/or the group Q⁺or Q⁻

includes a fluorinated oligoalkylene oxide unit, and/or the polymer backbone-forming unit -[A]- and/or the spacer X and/or the group Q⁺or Q⁻

are/is perfluorinated.

13. The cathode material of claim 1, wherein the at least one polymer electrolyte has or includes at least one repeating unit of the general chemical formula:

14. The cathode material of claim 13, comprising at least one copolymer of the general chemical formula:

15. The cathode material of claim 14, wherein the repeating unit:

16. The cathode material of claim 14, wherein the repeating unit:

17. The cathode material of claim 14, wherein the repeating unit:

18. The cathode material of claim 1, wherein the at least one cathode active material includes a sulfur-polymer composite and/or sulfur-carbon composite.

19. The cathode material of claim 1, wherein the at least one cathode active material includes a sulfur-polyacrylonitrile composite.

20. The cathode material of claim 1, further comprising at least one lithium conducting salt, the anion of the at least one lithium conducting salt and Q⁻

and Z⁻

being selected from the same anion class of sulfonylimides.

21. The cathode material of claim 1, wherein the spacer X includes:

at least one other negatively charged group Q⁻

that includes at least one sulfonylimide group and/or a sulfonate group, and a counterion Z⁺that is a lithium ion, or

at least one other positively charged group Q⁺that includes at least one ammonium ion group and/or at least one pyridinium group and/or at least one imidazolium group and/or at least one piperidinium group and/or at least one pyrrolidinium group and/or at least one phosphonium group and/or at least one guanidinium group and/or at least one morpholinium group and/or at least one uronium group and/or at least one thiouronium group, and a counterion Z⁻

that includes a lithium conducting salt anion.

22. The cathode material of claim 1, wherein the at least one polymer electrolyte includes at least one repeating unit of the general chemical formula: