Types of proton exchange membranes

2021-06-15 00:00

Hydrogen fuel cells are proton exchange membrane fuel cells. 1) Hydrogen reaches the anode through pipes or gas deflectors. Under the action of the anode catalyst, hydrogen molecules dissociate into positively charged hydrogen ions (protons), releasing negatively charged electrons. 2) Hydrogen ions reach the cathode through the electrolyte (proton exchange membrane); electrons reach the cathode through an external circuit.

The electrons create an electrical current in an external circuit, and with appropriate connections, power can be delivered to the load. 3) At the other end of the battery, oxygen (or air) reaches the cathode through pipes or gas deflectors; under the action of the cathode catalyst, oxygen reacts with hydrogen ions and electrons to form water. The hydrogen fuel cell uses a proton exchange membrane to ensure the complete reaction of hydrogen and oxygen. By the way, the efficiency of hydrogen fuel cells can reach more than 60%, and there are catalysts that do not use the precious metal platinum. Also, the efficiency of an internal combustion engine is limited by the Carnot cycle, so its efficiency is capped and always low.

Membrane materials also have the following disadvantages: 1) The production is difficult and the cost is high. The synthesis and sulfonation of perfluorinated materials are very difficult. The hydrolysis and sulfonation during the film formation process easily denature and degrade the polymer. 2) High requirements on temperature and water content, the working temperature of the series membrane is 7090. Exceeding this temperature will lead to a sharp drop in water content and conductivity, hindering the improvement of the electrode reaction speed, and the problem of catalyst poisoning can be overcome by appropriately increasing the working temperature; 3) Some hydrocarbons, such as methanol, have high permeability and are not suitable for direct methanol Proton exchange membranes for fuel cells (DMFCs). Therefore, in order to improve the performance of the proton exchange membrane, research on the improvement of the proton exchange membrane is also being carried out continuously.

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