A temperature effect on the electrode reactions was investigated in terms of activation energy of overpotential with 100 cm² class molten carbonate fuel cells. The overpotential is attributed to the resistance in the electrochemical reactions on electrodes, thus the activation energy reflects reaction characteristics of the electrodes. The activation energy was measured with electrochemical impedance spectroscopy (EIS) and inert gas step addition (ISA) methods. These methods revealed that the anodic overpotential had positive activation energies showing larger overpotential at higher temperature, whereas the cathodic overpotential had negative activation energies. In particular, the positive activation energy of anodic overpotential is a unique behavior which has not been treated before. The gas phase diffusion resistance in the porous electrode, calling pore diffusion resistance (PDR), would be responsible for the positive activation energy. On the other hand, the temperature dependence of reactant gas dissolution to the carbonate melts and transport through the carbonate film leads to negative activation energy because the cathode is covered by the relatively thick electrolyte film. Insignificant PDR effect is observed at the cathode through the activation energy of gas phase mass transfer resistance at the cathode.

用100 cm ²的过电势活化能研究了温度对电极反应的影响类熔融碳酸盐燃料电池。过电位归因于电极上电化学反应中的电阻，因此活化能反映了电极的反应特性。活化能通过电化学阻抗谱（EIS）和惰性气体逐步添加（ISA）方法进行测量。这些方法表明，阳极过电势具有正的激活能，在较高温度下显示出更大的过电势，而阴极过电势具有负的激活能。特别地，阳极超电势的正活化能是一种以前未曾处理过的独特行为。多孔电极中的气相扩散阻力称为孔扩散阻力（PDR），将负责产生正活化能。另一方面，由于阴极被相对较厚的电解质膜覆盖，因此反应物气体溶解到碳酸盐的温度依赖性熔化并通过碳酸盐膜传输会导致负活化能。通过在阴极处的气相传质阻力的活化能，在阴极处观察到微不足道的PDR效应。