Meyers et al. [18] proposed a more detailed one-dimensional model in 2006 to describe the generation of high cathode potential, as well as further performance degradation due to the uneven gas distribution within the fuel cell. This transient model takes into account the gas transmission along the thickness direction in the membrane electrode, as well as the gas concentration differences along the channel. Tang et al. [19] pointed out that after the fuel cell shuts down, the residual air and hydrogen would lead to an OCV of about 1.0 V. Thepresence hydrogen–oxygen interface divides the fuel cell cathode and anode into four regions, as shown in Fig. 5 [10]. Since regions B and C are connected to A through the proton exchange membrane, the potentials in regions A–C are all close to the open circuit voltage (about 1.0 V). Because the cathode potential is 1.0 V higher than the anode, thepotential in region D is up to 2.0 V. Owenjan et al. [20] showed how cathode carbon corrosion develops during start-up/shutdown, and proposed a reverse current model in 2007 to explain the formation of high cathode potential from the aspect of proton and electron movements. As shown in Fig. 6, they argued that the formation of the hydrogen-air interface causes the potential to decrease in the air-covered anode region, the protons move from the cathode to the anode in the opposite direction of the normal movement, forming an air-air cell in the air-filled portion. In order to sustain the oxygen reduction reaction (ORR) at the anode side of the air-air cell, the cathode potential increases until carbon oxidation occurs, supplying protons needed in the anode for ORR.
Meyers et al. [18] proposed a more detailed one-dimensional model in 2006 to describe the generation of high cathode potential, as well as further performance degradation due to the uneven gas distribution within the fuel cell. This transient model takes into account the gas transmission along the thickness direction in the membrane electrode, as well as the gas concentration differences along the channel. Tang et al. [19] pointed out that after the fuel cell shuts down, the residual air and hydrogen would lead to an OCV of about 1.0 V. Thepresence hydrogen–oxygen interface divides the fuel cell cathode and anode into four regions, as shown in Fig. 5 [10]. Since regions B and C are connected to A through the proton exchange membrane, the potentials in regions A–C are all close to the open circuit voltage (about 1.0 V). Because the cathode potential is 1.0 V higher than the anode, thepotential in region D is up to 2.0 V. Owenjan et al. [20] showed how cathode carbon corrosion develops during start-up/shutdown, and proposed a reverse current model in 2007 to explain the formation of high cathode potential from the aspect of proton and electron movements. As shown in Fig. 6, they argued that the formation of the hydrogen-air interface causes the potential to decrease in the air-covered anode region, the protons move from the cathode to the anode in the opposite direction of the normal movement, forming an air-air cell in the air-filled portion. In order to sustain the oxygen reduction reaction (ORR) at the anode side of the air-air cell, the cathode potential increases until carbon oxidation occurs, supplying protons needed in the anode for ORR.<br>
正在翻译中..