Membrane electrode in fuel cell

The Membrane electrode (MEA) is the core part of the fuel cell, it is the main site of electrochemical reaction between fuel and oxygen. The performance of membrane electrode directly determines the function and efficiency of fuel cell. Therefore, for the crack sensor based on the electrochemical reaction principle of fuel cells, only the membrane electrode with good performance can carry out the electrochemical reaction smoothly, so as to ensure the oxygen sensitivity of the air cathode of fuel cells. The sensitivity of fuel cells to oxygen is the basic working principle of crack sensors based on fuel cell electrochemistry. Good oxygen sensitivity determines the detection accuracy of the new sensor for cracks on the permeable outer surface. A membrane electrode is usually composed of three main parts: an electrolyte membrane, an anode in direct contact with fuel, and a cathode in contact with air (oxygen).

At present, the membrane electrode used in fuel cells is a kind of multi-channel diffusion electrode, which generally includes two parts: catalytic layer and diffusion layer. The catalytic layer is where the electrochemical reaction occurs at the three-phase interface, and the diffusion layer acts as the material needed to support the catalytic layer, collect the current and transfer the electrochemical reaction. Therefore, membrane electrodes need to have continuous channels for protons, electrons, reactants and products. The diffusion layer is mostly carbon paper or carbon cloth coated with microporous layer. The electrolyte membrane usually uses the all-gas sulfonic acid proton exchange membrane.