Fuel cell thermodynamic

Wang Y, Li L, Hu L, Zhuang L, Lu J, Xu B. 2003. A feasibility analysis for alkaline membrane direct methanol fuel cell Thermodynamic disadvantages versus kinetic advantages. Electrochem Commun 5 662. 

Demlrcl UB (2007) Direct liquid-feed fuel cells thermodynamic and environmental concerns. J Power Sources 169 239-246... 

Solid Oxide Fuel Cells, Thermodynamics Solid State Electrochemistry, Electrochemistry Using Solid Electrolytes... 

Solid Oxide Fuel Cells, Thermodynamics, Fig. 3 Themodynamic theoretical conversion efficiency for reforming SOFC and further lowering in efficiency due to the Joule loss and electrochemical oxygen permeation through the YSZ electrolyte for difference thickness... 

Solid Oxide Fuel Cells, Thermodynamics, Fig. 4 Chemical potential diagrams for the La-Mn-Zr-O and the La-Co-Zr-0 system and analyses in terms of the stabilization energy and the valence stability of transition metal oxides... 

In the previous section, we discussed fuel cell thermodynamics. However, in reality, fuel cell operation with an external load is much more practical than in a thermodynamic state. When a H2/air PEM fuel cell outputs power, the half-electrochemical reactions will proceed simultaneously on both the anode and the cathode. The anode electrochemical reaction expressed by Reaction (l.I) will proceed from H2 to protons and electrons, while the oxygen from the air will be reduced at the cathode to water, as expressed by electrochemical Reaction (l.II). For these two reactions, although the hydrogen oxidation reaction (HOR) is much faster than the oxygen reduction reaction (ORR), both have limited reaction rates. Therefore, the kinetics of both the HOR and the ORR must be discussed to achieve a better understanding of the processes occurring in a PEM fuel cell. 

At the cathode of a PEM fuel cell, a pure Pt surface is not easy to achieve because oxygen is present, leading to a mixed surface of Pt and PtO. Thus, the fuel cell thermodynamic open circuit voltage (OCV) at 25 °C is always... 

The temperature can significantly affect the electrode kinetics in PEM fuel cells. This section will discuss the effects of temperature on (i) fuel cell thermodynamics and OC V, (ii) the kinetics of both the HOR and the ORR, (iii) the proton conductivity and hydration of the membrane, and (iv) mass transfer. 

Our recent study indicated that the fuel cell OCV decreased with increasing temperature, as shown in Fig. 4.3 [58]. It can be seen that both the theoretical and the measured OCV decreased when the temperature increased from 23 to 120 °C. This was mainly because of the effect of temperature on the fuel cell thermodynamics and hydrogen crossover, which will be addressed in detail in Chapters 6 and 7, respectively. 

Wang, Y., Li, L., Hu, L., Zhuang, L., Lu, J. and Xu, B. A feasibility analysis for alkaline membrane direct methanol fuel cell thermodynamic disadvantages versus kinetic advantages , Electrochem. Commun., 5 (2003) 662-666. Yang, J. and Xu, J.J. Nanoporous amorphous manganese oxide as electrocatalyst for oxygen reduction in alkaline solutions , Electrochem, Commun., S (2003) 306-311. 

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