Polymer electrolyte membranes (PEMs) based on imidazole ring terminated flexible branches grafted on hybrid inorganic-organic polymers

• US 7,851,580 B2
• Filed: 05/28/2004
• Issued: 12/14/2010
• Est. Priority Date: 05/28/2003
• Status: Expired due to Fees

• Current Assignee: Toyota Motor Corporation, Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation), Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Li, Siwen, Li, Wen, Liu, Meilin, Sun, Qunhui
• Primary Examiner(s): Moore; Margaret G
• Application Number:
  US10/558,521
• Publication Number:
  US 20070099035A1
• Time in Patent Office: 2,391 Days
• Field of Search: 528/30, 528/38, 556/407, 556/428, 429/33
• US Class Current: 528/30
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 2325/26 Electrical properties
• CPC Class Codes: B01D 67/0006 by chemical reactions in-situ polymerisation, polycondensation, cross-linking or reaction for manufacturing composite membranes B01D69/125
• CPC Class Codes: B01D 67/0044 by chemical reaction
• CPC Class Codes: B01D 67/0048 by sol-gel transition
• CPC Class Codes: B01D 71/70 Polymers having silicon in the main chain, with or without sulfur, nitrogen, oxygen or carbon only
• CPC Class Codes: B01D 71/76 Macromolecular material not specifically provided for in a single one of groups B01D71/08 - B01D71/74 rubbers in general B01D71/24
• CPC Class Codes: B01D 71/78 Graft polymers
• CPC Class Codes: C08G 77/392 containing sulfur
• CPC Class Codes: C08J 2379/06 Polyhydrazides; Polytriazoles; Polyamino-triazoles; Polyoxadiazoles
• CPC Class Codes: C08J 5/2256 based on macromolecular compounds obtained by reactions other than those involving carbon-to-carbon bonds, e.g. obtained by polycondensation
• CPC Class Codes: C08L 83/08 containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 2300/0091 in the form of mixtures
• CPC Class Codes: H01M 8/1037 having silicon, e.g. sulfonated crosslinked polydimethylsiloxanes
• CPC Class Codes: H01M 8/1074 Sol-gel processes
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A composition of matter comprises a polymer network, including silicon atoms and oxygen atoms, a first organic side-chain attached to at least some silicon atoms within the polymer network comprising a flexible linking group and a terminal group, the terminal group including at least one atom providing a lone pair of electrons. The composition of matter can be used to form a proton-conducting membrane. In illustrative examples, the polymer network can be an organic-inorganic hybrid network and the terminal group can includes a nitrogen-containing heterocycle.

Claims

1. A proton-conducting material including a copolymerization product of at least a first silane and a second silane,

the first silane comprising a first silane group, a terminal group, and a linking group connecting the terminal group to the first silane group,

the terminal group including at least one atom providing a lone pair of electrons,

the proton-conducting material being a proton-conducting membrane,

the terminal group including an aromatic heterocycle having at least one atom selected from a group consisting of oxygen, nitrogen, and sulfur,

the linking group including a sulfoxy group.

2. The proton-conducting material of claim 1, wherein the aromatic heterocycle is a nitrogen-containing heterocycle.

3. The proton-conducting material of claim 2, wherein the nitrogen-containing heterocycle is imidazole, so that the terminal group includes an imidazole ring.

4. The proton-conducting material of claim 1, wherein the terminal group includes a benzimidazole group.

5. The proton-conducting material of claim 1, wherein the sulfoxy group includes a sulfur atom bound to a carbon atom of the aromatic heterocycle.

6. The proton-conducting material of claim 1, wherein the linking group includes at least one aromatic ring.

7. The proton-conducting material of claim 1, wherein the first silane or the second silane includes an acid group.

8. The proton-conducting material of claim 1, wherein the second silane is a tetraalkyloxysilane.

9. The proton-conducting material of claim 1, wherein the second silane is a bisalkyloxysilyl terminated organic polymer.

10. A fuel cell including:

a first electrode;

a second electrode; and

a proton-conducting membrane located between the first electrode and the second electrode,

the proton-conducting membrane including a proton-conducting material,

the proton-conducting material comprising a material formed from the copolymerization of at least three silanes, including a first silane, a second silane, and a third silane,

the first silane comprising a first silane group, a terminal group, and a linking group connecting the terminal group to the first silane group,

the terminal group including at least one atom providing a Ione pair of electrons

the terminal group of the first silane including an imidazole ring,

the second silane being a tetraalkoxysilane, and

the third silane including a flexible organic chain.

11. The fuel cell of claim 10, wherein the first silane has a structure represented by:

Z—

L—

Si(R₁)(R₂)(R₃),

where R₁, R₂, and R₃ represent an alkyl group, alkoxy group, hydroxyl group, or a hydrogen atom, wherein R₁, R₂, and R₃ are the same or different,

L represents the linking group,

and Z represents the terminal group, the terminal group including the imidazole ring.

12. The fuel cell of claim 10, wherein the proton-conducting membrane further includes free inorganic acid molecules.

13. A proton-conducting material, comprising

a polymer network, including silicon atoms and oxygen atoms;

and

organic side-chains attached to silicon atoms within the polymer network,

each organic side-chain comprising a linking group and a terminal group, the linking group connecting the terminal group to a silicon atom of the polymer network,

the terminal group including a heterocycle, the heterocycle including at least one atom chosen from a group consisting of nitrogen, oxygen, and sulfur,

the heterocycle being an aromatic heterocycle,

the polymer network being an inorganic-organic hybrid polymer network,

the proton-conducting material being a proton-conducting membrane,

the linking group including a sulfoxy group.

14. The proton-conducting material of claim 13, wherein the aromatic heterocycle is imidazole, so that the terminal group includes an imidazole ring.

15. The proton-conducting material of claim 13, wherein the terminal group includes a benzimidazole group.

16. The proton-conducting material of claim 13, wherein the sulfoxy group includes a sulfur atom bound to a carbon atom of the aromatic heterocycle.

17. The proton-conducting material of claim 13, wherein the linking group includes at least one aromatic ring.

18. The proton-conducting material of claim 13, further comprising acid groups bound to the polymer network.

19. The proton-conducting material of claim 13, wherein the hybrid inorganic-organic polymer network is formed by a sol-gel copolymerization reaction of a plurality of silane precursors.

20. The proton-conducting material of claim 13, further comprising free inorganic acid molecules.

21. A fuel cell including:

a first electrode;

a second electrode; and

a proton-conducting membrane located between the first electrode and the second electrode,

the proton-conducting membrane including the proton-conducting material of claim 13.

22. A process for preparing a silane compound, the process comprising:

providing a first compound, including a terminal group and a first reactive group, the terminal group including a heterocycle including at least one atom selected from a group consisting of nitrogen, oxygen, and sulfur;

providing a second compound, including a silane group and a second reactive group;

providing a reaction between the first reactive group and the second reactive group so as to prepare the silane compound, the silane compound having the terminal group connected to the silane group through a linking group,

the reaction being between a halogen atom and a thiol group, so that the linking group of the silane compound includes a sulfur atom, and

the process further including oxidizing the sulfur atom so that the linking group includes sulfoxy group.

23. The process of claim 22, wherein the heterocycle is an aromatic nitrogen-containing heterocycle.

24. The process of claim 23, wherein the terminal group includes an imidazole ring.

25. The process of claim 24, wherein the terminal group includes a benzimidazole group, the benzimidazole group including the imidazole ring.

26. The process of claim 23, wherein the linking group of the silane compound further includes at least one aromatic ring.

27. A silane compound, the silane compound comprising:

a silane group, the silane group being hydrolyzable,

a linking group, connected to the silane group, and

a terminal group, attached to the linking group so that the linking group interconnects the silane group and the terminal group,

the terminal group including an aromatic nitrogen-containing heterocycle,

the linking group including a sulfoxy group.

28. The silane compound of claim 27, wherein the terminal group includes an imidazole ring.

29. The silane compound of claim 28, wherein a sulfur atom of the sulfoxy group is directly attached to a carbon atom of the aromatic nitrogen-containing heterocycle.

30. The silane compound of claim 28, wherein the linking group includes at least one aromatic ring.

31. The silane compound of claim 27, wherein the terminal group includes a benzimidazole group.

32. A proton-conducting material including a copolymerization product of at least a first precursor and a second precursor,

the first precursor including:

a first polymerizable group,

a linking group, and

a terminal group, the terminal group being connected to the first polymerizable group through the linking group, the terminal group including an aromatic nitrogen-containing heterocycle; and

the second precursor, having a second polymerizable group,

the proton-conducting material being a proton-conducting membrane, and

the linking group including a sulfoxy group.

33. The proton-conducting membrane of claim 32, wherein the terminal group includes an imidazole ring.

34. The proton-conducting membrane of claim 32, a sulfur atom of the sulfoxy group being directly attached to a carbon atom of the aromatic nitrogen-containing heterocycle.

35. The proton-conducting membrane of claim 32, wherein the second precursor includes an acid group.

36. The proton-conducting membrane of claim 32, wherein the first polymerizable group and the second polymerizable groups are both silanes, the copolymerization being a sol-gel reaction.