A ceramic-based high-temperature proton exchange membrane cell CCM membrane electrode

Abstract

The application discloses a ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode, the CCM membrane electrode is obtained by adopting the following steps: soaking a ceramic proton exchange membrane in phosphoric acid, shaping, directly coating a catalyst slurry on the surface of the ceramic proton exchange membrane, and drying; and the working temperature of the CCM membrane electrode is 250-400 DEG C. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode solves the problems of the large three-phase interface resistance, the catalyst deactivation caused by phosphoric acid overflow and the battery performance decline of the GDE method commonly used for preparing the high-temperature fuel cell membrane electrode, and the membrane electrode has a higher temperature resistance, a higher working temperature and a wider application range.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell membrane electrodes, and specifically relates to a ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode. Background Technology

[0002] Traditional low-temperature fuel cells employ a direct-coating CCM (Chemical Membrane Electrode) fabrication process, where the catalyst is directly coated onto both sides of the proton exchange membrane to obtain a catalyst / proton exchange membrane assembly. In contrast, medium- and high-temperature fuel cells commonly use a GDE (Gas Diffusion Electrode) method to fabricate the membrane electrode, which involves depositing a catalyst layer onto the surface of a gas diffusion layer (GDL) to obtain the electrode, which is then hot-pressed onto both sides of the proton exchange membrane. This is because low-temperature proton exchange membranes have dry surfaces, allowing the binder to form bonds with the membrane surface. However, medium- and high-temperature proton exchange membranes have adsorbed phosphoric acid and are prone to absorbing water, resulting in a slippery surface, making them unsuitable for the direct-coating CCM fabrication process used in traditional low-temperature fuel cells. Summary of the Invention

[0003] The purpose of this invention is to provide a ceramic-based high-temperature proton exchange membrane electrode for fuel cells.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode, wherein the CCM membrane electrode is obtained by soaking a ceramic proton exchange membrane in phosphoric acid for shaping, then directly coating its surface with a catalyst slurry, and drying it. The operating temperature of the CCM membrane electrode is 250-400℃.

[0005] Furthermore, the ceramic material in the ceramic proton exchange membrane is one or a mixture of two or more of oxide ceramics, nitride ceramics, carbide ceramics, boride ceramics, or silicide ceramics; the oxide ceramic is Al2O3, ZrO2, TiO2, MgO, CaO, BeO, or ThO2; the nitride ceramic is Si3N4, BN, AlN, TiN, or Mg3N2; the carbide ceramic is SiC, WC, or B4C; the boride ceramic is B2Zr, TiB2, or LaB6; and the silicide ceramic is Ca2Si, Mg2Si, CrSi2, or MoSi2.

[0006] Furthermore, the mass concentration of phosphoric acid is 50%–85%, the soaking temperature is 25–120°C, and the soaking time is 6–72 hours. The shaping process involves wiping the surface of the ceramic proton exchange membrane after soaking in phosphoric acid to remove excess free phosphoric acid, and then laying it flat on a heating plate for shaping.

[0007] Furthermore, the catalyst slurry is composed of a binder, a proton conductor, a catalyst, and a solvent. The mass ratio of binder to proton conductor to catalyst is 1:(10-50):(0.5-5), and the solid content in the catalyst slurry is 5%-50%.

[0008] Furthermore, the adhesive is one or a mixture of two or more of the following: polybenzimidazole, polyvinylimidazole, polyvinylpyrrolidone, polyarylene piperidine, polyphosphonic acid, perfluorosulfonic acid resin, polyvinylidene fluoride, or polytetrafluoroethylene.

[0009] Furthermore, the proton conductor is one or a mixture of two or more of the following: solid acid, solid acid salt, heteropoly acid, heteropoly acid salt, organophosphonic acid, organophosphonate, or polymer containing phosphate groups. For example: solid acid or solid acid salt can be perovskite ceramic, β-Al2O3 ceramic, aluminosilicate, zirconate, cerate, phosphate, cesium salt, tungsten bronze or molybdenum bronze, etc.; heteropoly acid or heteropoly acid salt can be phosphotungstic acid, phosphomolybdic acid, silicotungstic acid or silicotomolybdic acid, etc.; organophosphonic acid or organophosphonate can be hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, ethylenediaminetetramethylidene phosphonic acid, hexamethylenediaminetetramethylidene phosphonic acid, diethylenetriaminepentamethylidene phosphonic acid, phytic acid, risedronic acid, alendronic acid or zoledronic acid, etc.; polymer containing phosphate groups can be polyvinylphosphonic acid, polyvinylphosphonate or polyphosphonate.

[0010] Furthermore, the catalyst is one or a mixture of two or more of the following: Fe, Co, Ni, Cu, Mn, Cr, V transition metal single atoms or single-atom clusters, transition metal alloys FeNi, FeCo, FeMn, CoNi, CoMn, FeCu, or Pt / C, PtPb / C, PtRu / C, PtCo / C, PtNi / C, Pt / WO3, Pt / MO3, Pt / TiO2, Pd / C, PdCo / C, Co / N / C, CoNi / C, Fe / N / C, Fe / CeO2, g-C3N4, Mxenes, metal / heteroatom doped graphene, two-dimensional MOF, or COF.

[0011] Furthermore, the solvent is an acidic solvent, or includes a main solvent and a co-solvent, wherein the main solvent is an acidic solvent; the acidic solvent is sulfuric acid, phosphoric acid, formic acid, acetic acid, propionic acid, methanesulfonic acid or hydrofluoric acid; and the co-solvent is N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide.

[0012] Furthermore, the coating process employs one or a combination of two or more of the following: transfer printing, spraying, scraping, and roller coating.

[0013] Furthermore, the ceramic-based high-temperature proton exchange membrane battery (CCM) electrode has a thickness of 20–200 μm, a proton conductivity of 0.01–0.20 S / cm, and a mechanical tensile strength of 5–100 MPa.

[0014] This invention provides a ceramic-based high-temperature proton exchange membrane electrode (CCM) for fuel cells, which solves the problems of high three-phase interface resistance, catalyst deactivation due to phosphoric acid overflow, and battery performance degradation that are commonly found in the preparation of high-temperature fuel cell CCMs using the GDE method. Furthermore, the CCM has higher temperature tolerance, higher operating temperature, and a wider range of applications. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0016] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0017] Example 1

[0018] This embodiment provides a ceramic-based high-temperature proton exchange membrane battery (CCM) membrane electrode, the preparation of which includes the following steps:

[0019] 1) Pretreatment of ceramic proton exchange membranes:

[0020] The SiO2 ceramic proton exchange membrane was immersed in 85% phosphoric acid at 100°C for 24 hours. After immersion, the membrane was removed, excess free phosphoric acid on the surface was wiped off with filter paper, and then it was laid flat on a heating plate at 50°C for shaping.

[0021] 2) Preparation of catalyst slurry:

[0022] Take polybenzimidazole, zirconium phosphate and Pt / C in a mass ratio of 1:5, add 9 mL formic acid and 1 mL DMF to a reaction flask, stir at a constant temperature for 6 h and then sonicate for 2 h to obtain a slurry with a mass volume concentration of 25%.

[0023] 3) The prepared catalyst slurry was directly coated onto the surface of the pretreated SiO2 ceramic proton exchange membrane and dried completely to obtain the CCM membrane electrode.

[0024] The CCM film electrode obtained according to the method of the embodiment has a thickness of 100 μm, a proton conductivity of 0.05 S / cm, and a mechanical tensile strength of 25 MPa.

[0025] Example 2

[0026] This embodiment provides a ceramic-based high-temperature proton exchange membrane battery (CCM) membrane electrode, the preparation of which includes the following steps:

[0027] 1) Pretreated ceramic proton exchange membrane:

[0028] The ZrO2 ceramic proton exchange membrane was immersed in 85% phosphoric acid and placed at 120°C for 16 hours. After that, it was removed, excess free phosphoric acid on the surface was wiped off with filter paper, and then it was laid flat on a heating plate at 80°C for shaping.

[0029] 2) Preparation of catalyst slurry:

[0030] Take polybenzimidazole, tungsten bronze and PtPd / C in a mass ratio of 1:10, add 8 mL formic acid and 2 mL DMAC to a reaction flask, stir at a constant temperature for 6 h and then sonicate for 2 h to obtain a slurry with a mass volume concentration of 10%.

[0031] 3) The prepared catalyst slurry was directly sprayed onto the surface of the pretreated ZrO2 ceramic proton exchange membrane, and after complete drying, the CCM membrane electrode was obtained.

[0032] The CCM film electrode obtained according to the method of this embodiment has a thickness of 80 μm, a proton conductivity of 0.08 S / cm, and a mechanical tensile strength of 20 MPa.

[0033] Example 3

[0034] This embodiment provides a ceramic-based high-temperature proton exchange membrane battery (CCM) membrane electrode, the preparation of which includes the following steps:

[0035] 1) Pretreated ceramic proton exchange membrane:

[0036] The BN ceramic proton exchange membrane was immersed in 85% phosphoric acid and placed at 80°C for 24 hours. After that, it was removed, excess free phosphoric acid on the surface was wiped off with filter paper, and then it was laid flat on a heating plate at 60°C for shaping.

[0037] 2) Preparation of catalyst slurry:

[0038] Take polybenzimidazole, phosphotungstic acid and Pt / C in a mass ratio of 1:8, add 8 mL formic acid and 2 mL NMP to a reaction flask, stir at a constant temperature for 4 h and then ultrasonically disperse for 1 h to obtain a slurry with a mass volume concentration of 20%.

[0039] 3) The prepared catalyst slurry was directly coated onto the surface of the pretreated BN ceramic proton exchange membrane and then completely dried to obtain the CCM membrane electrode.

[0040] The CCM film electrode obtained according to the method of this embodiment has a thickness of 80 μm, a proton conductivity of 0.04 S / cm, and a mechanical tensile strength of 18 MPa.

[0041] Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode, characterized in that: The CCM membrane electrode is obtained by soaking a ceramic proton exchange membrane in phosphoric acid for shaping, then directly coating its surface with catalyst slurry and drying it. The operating temperature of the CCM membrane electrode is 250-400℃. The phosphoric acid has a mass concentration of 50% to 85%, the soaking temperature is 25 to 120°C, and the soaking time is 6 to 72 hours. The shaping process involves wiping the surface of the ceramic proton exchange membrane after soaking in phosphoric acid to remove excess free phosphoric acid, and then laying it flat on a heating plate for shaping.

2. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode according to claim 1, characterized in that: The ceramic material in the ceramic proton exchange membrane is one or a mixture of two or more of oxide ceramics, nitride ceramics, carbide ceramics, boride ceramics or silicide ceramics.

3. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode according to claim 2, characterized in that: The oxide ceramics are Al2O3, ZrO2, TiO2, MgO, CaO, BeO, or ThO2; the nitride ceramics are Si3N4, BN, AlN, TiN, or Mg3N2; the carbide ceramics are SiC, WC, or B4C; the boride ceramics are B2Zr, TiB2, or LaB6; and the silicide ceramics are Ca2Si, Mg2Si, CrSi2, or MoSi2.

4. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode according to claim 1, characterized in that: The catalyst slurry is composed of a binder, a proton conductor, a catalyst, and a solvent. The mass ratio of binder:proton conductor:catalyst is 1:(10~50):(0.5~5), and the solid content in the catalyst slurry is 5%~50%.

5. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode according to claim 4, characterized in that: The adhesive is one or a mixture of two or more of the following: polybenzimidazole, polyvinylimidazole, polyvinylpyrrolidone, polyarylene piperidine, polyphosphonic acid, perfluorosulfonic acid resin, polyvinylidene fluoride, or polytetrafluoroethylene.

6. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode according to claim 4, characterized in that: The proton conductor is one or a mixture of two or more of the following: solid acid, solid acid salt, organophosphonic acid, organophosphonate, or polymer containing phosphate groups.

7. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode according to claim 4, characterized in that: The catalyst is one or a mixture of two or more of the following: Fe, Co, Ni, Cu, Mn, Cr, V transition metal single atoms or single-atom clusters, transition metal alloys FeNi, FeCo, FeMn, CoNi, CoMn, FeCu, or Pt / C, PtPb / C, PtRu / C, PtCo / C, PtNi / C, Pt / WO3, Pt / MO3, Pt / TiO2, Pd / C, PdCo / C, Co / N / C, CoNi / C, Fe / N / C, Fe / CeO2, g-C3N4, Mxenes, metal / heteroatom doped graphene, two-dimensional MOF, or COF.

8. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode according to claim 4, characterized in that: The solvent is an acidic solvent, or it may include a main solvent and a secondary solvent, wherein the main solvent is an acidic solvent.

9. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode according to claim 8, characterized in that: The acidic solvent is sulfuric acid, phosphoric acid, formic acid, acetic acid, propionic acid, methanesulfonic acid, or hydrofluoric acid; the co-solvent is N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, or dimethyl sulfoxide.

10. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode according to claim 1, characterized in that: The coating process is one or a combination of two or more of the following: transfer printing, spraying, scraping, and roller coating.

11. The ceramic-based high-temperature proton exchange membrane battery CCM membrane electrode according to claim 1, characterized in that: The ceramic-based high-temperature proton exchange membrane battery (CCM) electrode has a thickness of 20–200 μm, a proton conductivity of 0.01–0.20 S / cm, and a mechanical tensile strength of 5–100 MPa.