Direct methanol fuel cell membrane electrode structure and preparation method thereof

Abstract

The invention discloses a direct methanol fuel cell membrane electrode structure which comprises a positive electrode gas diffusion layer, a positive electrode micro-pore layer, a positive electrode catalytic layer, a proton membrane, a negative electrode catalytic layer, a negative electrode micro-pore layer, and a negative electrode gas diffusion layer, wherein the proton membrane is arranged in the middle of the direct methanol fuel cell membrane electrode structure. The direct methanol fuel cell membrane electrode structure is characterized in that the positive electrode gas diffusion layer and the negative electrode gas diffusion layer are made of carbon paper, carbon cloth or other porous conductive plates subjected to hydrophobic treatment; the PTFE contents of the positive electrode gas diffusion layer and the negative electrode gas diffusion layer are 1-50wt%; a positive electrode micro-pore layer is coated on the positive electrode gas diffusion layer; a negative electrode micro-pore layer is coated on the negative electrode gas diffusion layer; and the PTFE contents of the positive electrode micro-pore layer and the negative electrode micro-pore layer are generally identical, that is, are 2-50wt%, and the apertures of micro-pores are generally identical. The metal carrying capacity of a catalyst in the positive electrode catalytic layer is about 1-8mg / cm<2>, the metal carrying capacity of the negative electrode catalytic layer is within 0.1-6mg / cm<2>. The invention further discloses a method for preparing the direct methanol fuel cell membrane electrode structure.

Description

Technical field [0001] The invention relates to a membrane electrode of a direct methanol fuel cell and a preparation method thereof. Background technique [0002] Direct methanol fuel cell (DMFC) uses liquid fuel, which is convenient to carry and easy to fill. In addition, it has a simple structure, runs at near room temperature, is reliable in operation, and has high energy conversion efficiency. The application of DMFC in small or portable power sources has attracted much attention. [0003] figure 1 It is a schematic diagram of the traditional DMFC using methanol dilute solution. The methanol aqueous solution flows through the flow channel in the anode current collecting plate, and an electrochemical reaction occurs in the catalytic layer on the anode side of the membrane electrode structure (MEA) to generate carbon dioxide, hydrogen ions, and electrons. Hydrogen ions pass through the proton conductive membrane to reach the cathode side, and electrochemically react with oxyg...

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Problems solved by technology

[0011] The present invention overcomes the shortcomings of the prior art in utilizing the hydraulic pressure difference of the cathode microporous layer to solve the problem of anode water seepage in the internal circulation of water, and provides a method that not only achieves the purpose of water backflow, but also prevents anode water from leaking out. Oozed Direct Methanol Fuel Cell Membrane Electrode Structure and Preparation Method

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