STUDY OF CO POISONING IN A PHOSPHORIC-ACID FUEL-CELL USING A SINGLE-CELL WITH MULTIREFERENCE ELECTRODES

The influence of CO poisoning upon a Phosphoric acid fuel cell was studied using a single cell with twelve-reference electrodes (RHEs). Due to CO poisoning, remarkable and well-balanced potential shift occurred at the fuel outlet area. The potential shift at the fuel outlet area caused current convergence into the fuel outlet area. The increase in current density at the fuel inlet area due to the current convergence enlarges the overvoltage mainly at the cathode side. The voltage loss due to CO poisoning has been believed to be the increase of overvoltage only at the anode. In the case of a single cell, however, it was found that the increase of overvoltage at the cathode caused by the current convergence into the fuel inlet area is the major part of the voltage loss. CO-T potential maps were obtained from the data at various CO concentration and temperature. A CO-T potential map of maximum cathode potential showed clearly that CO poisoning does not increase the cathode corrosion.