Characterization of a 100 cm² Class Molten Carbonate Fuel Cell with Current Interruption

A current‐interrupter method has been employed to measure the potential relaxation from output to open‐circuit voltage (OCV). The relaxation process represents the voltage losses of molten‐carbonate fuel cells which are composed of ohmic loss (η_IR), reaction overpotential (η_Re), and Nernst loss (ΔE_loss). The responses of current interruption for a 100 cm² class Li‐Na carbonate fuel cell were measured as functions of temperature, gas utilization, and oxidant gas composition . The single cell showed three different relaxation patterns of time regions during potential decay to OCV; the shortest time region (less than 20 μs) is due to η_IR, an intermittent time region (20 μs to 150 ms) is due to η_Re, and the residual time region is due to ΔE_loss. The further analysis of η_Re data is consistent with the argument that the oxygen reduction reaction in the single cell is controlled by a mixed diffusion process of superoxide ion and .