US-12626945-B2 - Tetravalent boron-containing proton-exchange solid supports and methods of making and using tetravalent boron-containing proton-exchange solid supports

Abstract

A proton exchange solid support includes a porous polymer network including a polymer. The polymer includes a tetravalent boron-based acid group in a side chain of the polymer, and the tetravalent boron-based acid group includes a boron atom having a negative formal charge. A cation is ionically linked to the boron atom.

Inventors

• Sukanta Bhattacharyya
• Daniel Sobek

Assignees

• 1S1 ENERGY, INC.

Dates

Publication Date

20260512

Application Date

20230113

Claims (11)

1. 1 . A method of making a proton-exchange solid support, comprising: modifying a hydroxyl group of an acid group with a tetravalent boron-based acid group in a side chain of a polymer of a porous polymer network, wherein the tetravalent boron-based acid group comprises a boron atom covalently bonded to four atoms and having a negative formal charge; and ionically linking a cation to the boron atom.
2. 2 . The method of claim 1 , wherein the side chain of the polymer comprises an alkyl chain of length m, where m ranges from one (1) to thirty (30), and wherein the alkyl chain is substituted or unsubstituted.
3. 3 . The method of claim 1 , wherein the tetravalent boron-based acid group has the general formula (O)B(Z 1 )(Z 2 )(Z 3 ) where O is an oxygen atom included in the side chain of the polymer, B is the boron atom, and Z 1 , Z 2 , and Z 3 are the same or different and each represents an alkyl group, an alkoxy group, an alkyloxycarbonyl group, an aryl group, an aryloxy group, or a fluoro group.
4. 4 . The method of claim 1 , wherein the boron atom is covalently bonded to at least one atom other than oxygen.
5. 5 . The method of claim 1 , wherein the polymer comprises an ionomer.
6. 6 . The method of claim 1 , wherein the polymer comprises a sulfonic acid-functionalized polymer and the acid group comprises a sulfonic acid group.
7. 7 . The method of claim 1 , wherein the polymer comprises a carboxylic acid-functionalized polymer and the acid group comprises a carboxylic acid group.
8. 8 . The method of claim 1 , wherein the polymer comprises a phosphonic acid-functionalized polymer and the acid group comprises a phosphonic acid group.
9. 9 . The method of claim 8 , wherein the phosphonic acid-functionalized polymer comprises a polyvinylphosphonic acid polymer.
10. 10 . The method of claim 1 , wherein the polymer comprises a phosphate-functionalized polymer.
11. 11 . The method of claim 10 , wherein the phosphate-functionalized polymer comprises a polybenzimidazole polymer doped with phosphoric acid.

Description

RELATED APPLICATIONS The present application is a continuation application of U.S. patent application Ser. No. 17/521,735, filed Nov. 8, 2021, which is a continuation of International Patent Application No. PCT/US2021/038956, filed Jun. 24, 2021, which claims priority to U.S. Provisional Patent Application No. 63/109,943, filed Nov. 5, 2020, each of which is hereby incorporated by reference in its entirety. U.S. patent application Ser. No. 17/521,735 is also a continuation-in-part of International Patent Application No. PCT/US2021/029705, filed Apr. 28, 2021, which also claims priority to U.S. Provisional Patent Application No. 63/109,943, filed Nov. 5, 2020, each of which is hereby incorporated by reference in its entirety. BACKGROUND INFORMATION Proton-exchange solid supports may be used in proton exchange membranes (PEMs), which are semipermeable membranes that are engineered to transport protons (H+) while being impermeable to gases such as hydrogen (H2) and oxygen (O2). PEMs may be used in hydrogen fuel cells and water electrolysis systems under acidic conditions. PEMs may be composed of a mechanically and chemically resistant particles and/or a porous framework with highly acidic functional groups. For example, Nafion-based proton exchange membranes contain a polytetrafluoroethylene (PTFE) porous structural framework with sulfonic acid groups. The easily dissociable sulfonic acid groups serve as proton transport agents in the membrane. SUMMARY The following description presents a simplified summary of one or more aspects of the methods and systems described herein in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects of the methods and systems described herein in a simplified form as a prelude to the more detailed description that is presented below. In some illustrative examples, a boron-containing proton-exchange solid support comprises a proton-exchange solid support comprising an oxygen atom and a tetravalent boron-based acid group comprising a boron atom covalently bonded to the oxygen atom. In some illustrative examples, a boron-containing proton-exchange solid support has general formula (Ia), (Ib), (Ic), or (Id): wherein: [SS] represents a solid support;X1 represents a substituent group having formula (IIa), (IIb), (IIc), or (IId): X2 represents a group having formula (IIIa) or (IIIb): Y1 and Y2 are the same or different and each represent a tetravalent boron-based acid group having formula (IV): where the boron (B) atom of formula (IV) is covalently bonded to the oxygen (O) atom of X1 or X2, and Z1, Z2, and Z3 are the same or different and each represents an alkyl group, an alkoxy group, an alkyloxycarbonyl group, an aryl group, an aryloxy group, or a fluoro group; andR represents a C1 to C30 alkyl linker chain and optionally has one or more pendant moieties, which may be the same or different for each atom in the linker chain and which may comprise hydrogen, a hydroxyl group, a fluoro group, a chloro group, a dialkylamino group, a cyano group, a carboxylic acid group, a carboxylic amide group, a carboxylic ester group, an alkyl group, an alkoxy group, and an aryl group. In some illustrative examples, a method of making a boron-containing proton-exchange solid support comprises modifying a proton-exchange solid support with a tetravalent boron-based acid group. In some illustrative examples, a membrane electrode assembly comprises a cathode, an anode, and a proton exchange membrane positioned between the cathode and the anode, the proton exchange membrane comprising a proton-exchange solid support comprising an oxygen atom and a tetravalent boron-based acid group comprising a boron atom covalently bonded to the oxygen atom. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate various embodiments and are a part of the specification. The illustrated embodiments are merely examples and do not limit the scope of the disclosure. Throughout the drawings, identical or similar reference numbers designate identical or similar elements. FIG. 1A shows an illustrative configuration of a solid support implemented as a porous structural framework. FIG. 1B shows another illustrative configuration of a solid support implemented as a solid support particle. FIGS. 2A and 2B show illustrative reaction schemes for synthesizing a boron-containing proton-exchange solid support presenting a tetravalent boron-based acid group linked to a sulfur (S) atom through an oxygen (O) atom. FIGS. 3A and 3B show illustrative reaction schemes for synthesizing a boron-containing proton-exchange solid support presenting a tetravalent boron-based acid group linked to a carbon (C) atom through an oxygen (O) atom. FIGS. 4A and 4B show an illustrative rea