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CN-121983593-A - Design and application of hierarchical porous catalytic layer for constructing high-drainage porous membrane electrode based on micro-nano bubbles

CN121983593ACN 121983593 ACN121983593 ACN 121983593ACN-121983593-A

Abstract

The invention relates to a method for preparing a high-drainage porous membrane electrode grading porous catalytic layer based on micro-nano bubbles, which comprises the steps of taking hydrogen peroxide as a bubble source, generating oxygen bubbles under the catalysis of carbon-supported platinum, and constructing the high-drainage porous membrane electrode by taking the micro-nano bubbles as a template. The invention constructs the membrane electrode with high porosity, effectively prevents the liquid water from blocking in the pores, and relieves the flooding phenomenon in the battery. The invention avoids the shrinkage and agglomeration of catalyst particles, and obtains the porous membrane electrode graded porous catalytic layer with high water drainage. The invention also provides application of the porous membrane electrode in the field of fuel cells.

Inventors

  • LIU JINYING
  • MAO QINQIN
  • YU LIPEI
  • LI JUN
  • HAN LILI

Assignees

  • 福州大学

Dates

Publication Date
20260505
Application Date
20260209

Claims (6)

  1. 1. A method for preparing a hierarchical porous catalytic layer of a high-drainage porous membrane electrode based on micro-nano bubbles is characterized by taking hydrogen peroxide as a bubble source, generating oxygen bubbles under the catalysis of carbon-supported platinum, and constructing the high-drainage porous membrane electrode by taking the micro-nano bubbles as a template, and specifically comprises the following steps: dissolving a carbon-supported platinum catalyst PtC and Nafion solution in ethanol and water to obtain a solution, carrying out ultrasonic treatment on the solution, then dripping the solution on carbon paper at 80 ℃, dripping hydrogen peroxide solution in the coating process, and drying in a vacuum freeze drying box after air drying.
  2. 2. The method of claim 1, wherein the mass fraction of PtC is 40% and the ratio of PtC to Nafion solution is such that the mass fraction of Nafion is 60% of the mass fraction of C in PtC.
  3. 3. The method of claim 1, wherein the volume ratio of ethanol to water is 4:1.
  4. 4. The method according to claim 1, wherein the hydrogen peroxide is added dropwise in an amount of 100 uL and the mass fraction of hydrogen peroxide is 1-2%.
  5. 5. The method of claim 1, wherein the vacuum freeze drying time is 8 hours.
  6. 6. The membrane electrode with high porosity is characterized in that the membrane electrode is prepared by the method of any one of claims 1-5, and can prevent liquid water from blocking in pores and relieve flooding phenomenon in a battery.

Description

Design and application of hierarchical porous catalytic layer for constructing high-drainage porous membrane electrode based on micro-nano bubbles Technical Field The invention relates to the technical field of fuel cells, in particular to a design and application of a hierarchical porous catalytic layer for constructing a porous membrane electrode with high drainage property based on micro-nano bubbles. Background Along with the rapid development of economy and culture, people have a continuously deepened understanding of natural environment. It is found that the excessive dependence and uncontrolled exploitation and use of petroleum in the past causes rapid consumption of fossil fuel, and then serious environmental pollution and energy shortage problems are caused, so that searching for clean and efficient alternative energy sources and developing new materials become one of important problems of common concern of governments and even the whole people. The proton exchange membrane fuel cell is an efficient and environment-friendly energy conversion technology and has the potential of solving global energy and environmental challenges. Research shows that the hydrogen energy and hydrogen fuel cell technology is expected to be applied to the fields of automobiles, portable power generation, fixed power stations and the like in a large scale. With the development of fuel cell technology, for practical vehicle-mounted proton exchange membrane fuel cell systems, the Membrane Electrode (MEA) generally tends to be thinner, has better water transmission performance, is easy to generate water flooding faults, generates more water and has higher working pressure, and the gaseous water is easier to liquefy, so that a Gas Diffusion Layer (GDL) and a runner are blocked, the mass transfer of reaction gas is blocked, reaction undergas is caused, and the performance of a galvanic pile is reduced and meanwhile the durability of the galvanic pile is damaged. Therefore, improving fuel cell water management is critical to improving cell performance and extending cell life. The water management of Proton Exchange Membrane Fuel Cells (PEMFCs) is mainly to ensure the water balance of the PEMFC, and the effective water management is to drain the redundant water of the cells without causing dehydration of the proton exchange membrane. In the running process of the battery, liquid water generated by external humidification and cathodic oxygen reduction reaction is combined with the proton exchange membrane to ensure the full hydration state of the membrane, and the rest liquid water reaches the flow field through the pores of the catalytic layer and the gas diffusion layer by virtue of capillary effect, and finally is discharged out of the battery through the shearing force and capillary effect of the airflow in the flow field. If the cell contains too much water, the liquid water will clog the pores of the porous medium, thus flooding the cathode. At this time, the reactant gas is less likely to be transported to the Catalyst Layer (CL), and the cell activation loss and the concentration loss increase, and eventually the discharge performance is greatly reduced. If the water content of the battery is too small, the wettability of the film is poor, the ionic conductivity of the film is lowered, ohmic loss of the battery is increased, and finally, the discharge performance is lowered. Therefore, reasonable control of the water content in the battery is critical to high performance stable operation of the battery. The most important catalyst in the current PEMFC operation process is a noble metal Pt-based catalyst, which has higher activity, but has poor durability, scarce resources and high price, so that large-scale operation is under great pressure. In general, the catalytic activity of a catalyst is not only related to the intrinsic catalytic ability, but also depends to a large extent on the surface structure of the catalyst. The development of new catalysts and support materials is therefore only a part of the technology of propulsion fuel cells. Without simultaneously improving the understanding of the CL structure versus performance relationship, fuel cells will not reach the technical maturity required to achieve widespread commercialization. The morphology of the CL is generally determined by the structure and method of manufacture of the support material, both of which play a role in shaping the morphology and performance of the CL. The ideal CL structure is an optimized balance between conductivity, proton conductivity, gaseous reactant transport, and catalyst accessibility. The CL slurry is prepared from a catalyst, nafion solution and a dispersing agent according to a certain proportion, and then is uniformly mixed by ultrasonic, and the MEA is prepared by ultrasonic spraying. The transport channels of the reactant gases, electrons, protons and generated water are in a disordered state, resulting in strong concentratio