The fuel cell is oxidized by the fuel at the anode and the oxidant is reduced at the cathode. If gaseous fuel (hydrogen) is continuously supplied on the anode (ie, the negative electrode of the external circuit, also known as the fuel electrode), and oxygen (or air) is continuously supplied on the cathode (ie, the positive electrode of the external circuit, also known as the air electrode), Electrochemical reactions can occur continuously on the electrodes and an electric current can be generated. It can be seen that the fuel cell is different from the conventional battery in that its fuel and oxidant are not stored in the battery, but in a storage tank outside the battery. When it is working (outputting current and doing work), it needs to continuously input fuel and oxidant into the cell and discharge reaction products at the same time. So in the way it works, it is similar to a regular gasoline or diesel generator. Since fuel and oxidant are continuously fed into the cell when the fuel cell is working, the fuel and oxidant used in the fuel cell are both fluid (gas or liquid). The most commonly used fuels are pure hydrogen, various hydrogen-rich gases (such as reformed gas) and some liquids (such as methanol aqueous solution), and the commonly used oxidants are pure oxygen, purified air and other gases and some liquids (such as peroxides). aqueous solutions of hydrogen and nitric acid, etc.).
The function of the fuel cell anode is to provide a common interface for the fuel and the electrolyte, to catalyze the oxidation of the fuel, and to transmit the electrons generated in the reaction to the external circuit or to the current collector plate and then to the external circuit. The role of the cathode (oxygen electrode) is to provide a common interface for oxygen and electrolyte, catalyze the reduction of oxygen, and transfer electrons from the external circuit to the reaction site of the oxygen electrode. Since most of the reactions occurring on the electrodes are multiphase interfacial reactions, in order to increase the reaction rate, the electrodes are generally made of porous materials and coated with electrocatalysts.
The role of the electrolyte is to transport the ions generated in the electrode reaction between the fuel electrode and the oxygen electrode, and to prevent the direct connection between the electrodes.
transfer electrons.
The role of the separator is to conduct ions, prevent the direct transfer of electrons between electrodes, and separate oxidants and reductants. Therefore the diaphragm
Must be resistant to electrolyte corrosion and insulation, and have good resistance to wetting.
