Catalytic electrode of proton exchange membrane fuel cell, battery provided with same and preparation method thereof

Abstract

The invention relates to a catalytic electrode of a proton exchange membrane fuel cell, a cell provided with the same and a preparation method thereof. The catalytic electrode comprises a conductive carrier layer with a net-shaped structure, and a proton conductive monomer and a catalyst which are located on the surface of the conductive carrier layer and in the net-shaped structure; the thickness of the conductive carrier layer is 1-10 microns; the cell provided with the catalytic electrode adopts the catalytic electrode to replace a cathode catalyst layer; the preparation method comprises the following steps of: S1, manufacturing the conductive carrier layer; S2, supporting a catalyst; S3, supporting the proton conductive monomer; and S4, transferring the conductive carrier layer. Almost catalysts, the proton conductive monomer and a pore can form an effective three-phase interface and the utilization efficiency of the catalyst is greatly improved; a water flooding phenomenon caused by the fact that the thickness smaller than 1 micron does not occur and a phenomenon that the conductive property is decreased, caused by the fact that the thickness is more than 10 microns also does not occur; the fuel cell adopting the catalyst can keep relatively long service life in a frequent starting-stopping automobile application environment.

Description

technical field [0001] The invention relates to the field of proton exchange membrane batteries, in particular to a catalytic electrode of a proton exchange membrane fuel cell, a battery with the same and a preparation method. Background technique [0002] A proton exchange membrane fuel cell (PEMFC) is a power generation device that directly converts the chemical energy of hydrogen into electrical energy through an electrochemical reaction. It has the advantages of zero emission, no pollution and high fuel efficiency. The basic reaction principle of the proton exchange membrane fuel cell is that the fuel gas hydrogen undergoes a hydrogen oxidation reaction at the anode and loses electrons to become protons. After combining with water, the protons migrate to the cathode through the proton exchange membrane, and generate oxygen with oxygen and electrons from the external circuit. The reduction reaction (Oxygen Reduction Reaction, ORR) produces water, and the electrons form a...

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Problems solved by technology

[0004] The existing carbon black-supported Pt catalysts cannot meet the commercial needs of fuel cells, and the existing problems mainly include:

[0005] (1) When the carbon black-supported Pt catalyst is made into an electrode, it must be mixed with the proton-conducting monomer solution. The electrochemical reaction can only occur at the contact interface between the catalyst and the proton-conducting monomer solution. In the black micropores, it is not wrapped by the proton-conducting monomer solution, and an effective three-phase interface (catalyst, pore, and proton-conducting monomer interface) cannot be formed, so this part of Pt does not play any catalytic role, resulting in a catalyst use efficiency decreased, thereby reducing the overall catalytic activity

In general, the use efficiency of Pt in membrane electrodes can only reach 60-70%.

[0006] (2) The fuel cell will generate a high potential (>1.0V) when it is started / stopped, and the catalyst carrier carbon black in the electrode will be oxidized at this high potential, resulting in the agglomeration and loss of the Pt catalyst it supports. lead to a significant decrease in catalytic performance

This greatly limits the application of fuel cells in the automotive industry

[0007] (3) In the case of a certain electrode catalyst loading, the thickness of the prepared catalytic electrode is inversely proportional to the loading of Pt metal on the carbon black. Since the loading of Pt catalyst is difficult to be higher than 60%, it is limited. The thickness of the cathode catalytic electrode is generally more than 10 microns. A thicker cathode catalytic electrode increases the path of proton diffusion from the proton exchange membrane to the cathode reaction area, which increases the proton diffusion plan and decreases the battery output power.

However, the catalyst layer is too thin and hydrophilic so that the reaction water that the catalyst layer can accommodate is extremely limited, and it is prone to flooding, that is, a small amount of water generated can completely submerge the catalyst layer, which prevents the diffusion of reactant oxygen to the surface of the catalyst. channels, so that oxygen can only diffuse to the surface of the catalyst through water, which greatly increases the diffusion polarization and makes the battery performance drop sharply

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