CN-117013024-B - Membrane electrode for high-temperature proton exchange membrane fuel cell and preparation method thereof

CN117013024BCN 117013024 BCN117013024 BCN 117013024BCN-117013024-B

Abstract

The invention discloses a membrane electrode for a high-temperature proton exchange membrane fuel cell and a preparation method thereof, wherein the membrane electrode is provided with an ionomer layer, and is of a multi-layer structure sequentially composed of a conductive substrate, a catalytic layer, an ionomer layer, a high-temperature proton exchange membrane, an ionomer layer, a catalytic layer and a conductive substrate, wherein the ionomer layer takes one or more polymers in polybenzimidazole or derivatives thereof as a main component, and is doped with carbon powder or one or more conductive agents in derivatives thereof to form a composite material, and the ionomer layer is formed on the surface of the catalytic layer. The membrane electrode in the invention constructs more three-phase interface sites by controlling electrolyte distribution represented by phosphoric acid through introducing the structure of the ionomer layer, has high peak power density and high current density, has simple preparation process and low cost, is applied to membrane electrodes of various high-temperature proton exchange membrane fuel cells, and has large-scale production application potential.

Inventors

KE CHANGCHUN
LUO JIANBIN
ZHANG JUNLIANG
ZHUANG XIAODONG
JIANG WENXING
WAN QIQI
HE JINYI

Assignees

上海交通大学

Dates

Publication Date: 20260512
Application Date: 20230904

Claims (3)

1. A membrane electrode for a high temperature proton exchange membrane fuel cell, characterized in that the membrane electrode is provided with an ionomer layer, and is a multi-layer structure composed of a conductive substrate, a catalytic layer, an ionomer layer, a high temperature proton exchange membrane, an ionomer layer, a catalytic layer and a conductive substrate in sequence, wherein the ionomer layer takes one or more polymers in polybenzimidazole or derivatives thereof as a main component, and is doped with one or more conductive agents in carbon powder or derivatives thereof to form a composite material, and the ionomer layer is formed on the surface of the catalytic layer; the carrying capacity of one or more polymers in polybenzimidazole or derivatives thereof in the ionomer layer is 0.1-0.5 mg cm -2 ; the conductive substrate is carbon paper or carbon cloth with a gas diffusion layer and/or a microporous layer; the catalytic layer is a composite material formed by a Pt-based catalyst formed by a deposition process and a hydrophobic adhesive, wherein the mass ratio of the hydrophobic adhesive to the Pt-based catalyst is 1:5-20, and the hydrophobic adhesive is selected from polytetrafluoroethylene and/or polyvinylidene fluoride; the high temperature proton exchange membrane is one or more polymers in acid-treated polybenzimidazole or derivatives thereof.
2. The method for preparing a membrane electrode for a high temperature proton exchange membrane fuel cell as claimed in claim 1, comprising the steps of: (1) Taking one or more of water, ethanol or isopropanol as a dispersing agent, adding Pt-based catalyst powder as an active ingredient and a suspension of polytetrafluoroethylene and/or polyvinylidene fluoride as a hydrophobic adhesive, and performing ultrasonic treatment on the obtained mixed slurry for 5-120min to obtain catalyst slurry; (2) The catalyst sizing agent obtained in the step (1) is coated on a conductive substrate by adopting an air spraying method, an electrostatic spraying method, an ultrasonic spraying method, a knife coating method, a screen printing method or a rolling method, and is dried for 0.5-4 hours at 60-80 ℃ to obtain the conductive substrate with the catalytic layer; (3) Placing the conductive substrate with the catalytic layer obtained in the step (2) at 200-400 ℃ for sintering for 1-5h and taking out to obtain a gas diffusion electrode; (4) Taking one or more of dimethylformamide, dimethylacetamide, dimethyl sulfoxide or N-methyl-2-pyrrolidone as a dispersing agent, adding one or more polymers in polybenzimidazole or derivatives thereof, wherein the mass ratio of solid to liquid is 1:20-500, and heating the mixed solution at 100-250 ℃ until the polymers are completely dissolved to obtain an organic solution; (5) Coating the organic solution obtained in the step (4) on the surface of the catalytic layer by adopting air spraying, electrostatic spraying, ultrasonic spraying, a knife coating method, a screen printing method or a rolling method, and drying for 0.5-3h at 80-160 ℃ to obtain an ionomer layer; (6) Immersing one or more polymer films in polybenzimidazole or derivatives thereof with the thickness of 10-35 microns in a mixture of one or more of phosphoric acid, hydrochloric acid or sulfuric acid in any proportion for 0.5-10h at the temperature of 80-120 ℃ to obtain a high-temperature proton exchange membrane; (7) And placing the gas diffusion electrode, the high-temperature proton exchange membrane and the gas diffusion electrode in sequence to form a sandwich structure, and hot-pressing for 1-8min at 100-150 ℃ and 0.1-0.4MPa to obtain the membrane electrode.
3. The use of the membrane electrode for a high temperature proton exchange membrane fuel cell of claim 1 in a high temperature proton exchange membrane fuel cell.

Description

Membrane electrode for high-temperature proton exchange membrane fuel cell and preparation method thereof Technical Field The invention belongs to the field of electrode materials, and particularly relates to a membrane electrode for a high-temperature proton exchange membrane fuel cell and a preparation method thereof. Background The high-temperature proton exchange membrane fuel cell which works at 120-200 ℃ can perform oxidation-reduction reaction in the membrane cell by using hydrogen, methanol, ethanol, hydrocarbon and other compounds as fuel, and can effectively convert chemical energy of the fuel into electric energy and heat energy. Compared with a low-temperature proton exchange membrane fuel cell, the fuel cell has higher tolerance to impurity fuels such as CO, quicker reaction kinetics and simpler water management system, so that the integrated system is easy to realize, and further the large-scale application is promoted, and the fuel cell has great advantages and application prospects as a power generation device. Although high temperature proton exchange membrane fuel cells have good prospects, the technology still has the drawbacks to be solved, such as lower power density, lower battery life, etc. Because of the high temperature proton exchange membrane fuel cell, the conductivity of the proton membrane is not derived from water, but from phosphoric acid. Therefore, before the battery is assembled, the high-temperature proton exchange membrane is generally subjected to phosphoric acid soaking treatment so as to have certain conductivity. However, during assembly and long-term operation, phosphoric acid is lost in large amounts, resulting in catalyst poisoning and a decrease in conductivity of the high temperature proton exchange membrane, which in turn results in a decrease in power density. Document (International Journal of Hydrogen Energy,2020,45,1008-1017) reports a high temperature proton exchange membrane with a three-layer polybenzimidazole structure for controlling the electrolyte distribution of a high temperature proton exchange membrane fuel cell, which is maintained at 0.65V after activation and peak power 359mW cm -2 after cell test at a current load of 0.2A cm -2. Literature (Nano Energy,2021,93,106829) reports a membrane electrode structure with single layer graphene for controlling electrolyte distribution of a high temperature proton exchange membrane fuel cell, which is maintained at 0.60V after activation and peak power of 470mW cm -2 after cell test loaded with current of 0.49A cm -2. Chinese patent (publication No. CN 105742649B) discloses a membrane electrode of a high-temperature proton exchange membrane fuel cell and a preparation method thereof, and the distribution of electrolyte is better controlled by carrying out acid treatment on a gas diffusion electrode in advance before press-fitting the membrane electrode. Under this method, the current density at 0.6V was 0.3A cm -2, and the peak power was 302mW cm -2. In summary, the current literature reports and the published patents that membrane electrodes for high temperature fuel cells control electrolyte distribution mainly through structural design, but still have lower current density and peak power density, which need to be further improved. Disclosure of Invention The main object of the present invention is to provide a membrane electrode for a high temperature proton exchange membrane fuel cell, adding an ionomer layer between the catalytic layer and the high temperature proton exchange membrane. Another object of the present invention is to provide a method for preparing the membrane electrode for a high temperature proton exchange membrane fuel cell. In order to achieve the above purpose, the invention adopts the following technical scheme: The invention provides a membrane electrode for a high-temperature proton exchange membrane fuel cell, which is a multi-layer structure sequentially composed of a conductive substrate, a catalytic layer, an ionomer layer, a high-temperature proton exchange membrane, the ionomer layer, the catalytic layer and the conductive substrate, wherein the ionomer layer takes one or more polymers in polybenzimidazole or derivatives thereof as main components, is doped with carbon powder or one or more conductive agents in derivatives thereof to form a composite material, and the ionomer layer is formed on the surface of the catalytic layer. Preferably, the loading amount of one or more polymers in the polybenzimidazole or the derivative thereof in the ionomer layer is 0.1-0.5 mg cm -2. Preferably, the conductive substrate is carbon paper or carbon cloth with a gas diffusion layer and/or a microporous layer. Preferably, the catalytic layer is a composite material formed by a Pt-based catalyst formed by a deposition process and a hydrophobic adhesive, wherein the mass ratio of the hydrophobic adhesive to the Pt-based catalyst is 1:5-20, and the hydrophobic adhesive is selected from pol