Hydrogen-ceria electrodes

Ceria-based electrodes 12.7.2.1 Electrodes for hydrogen-based fuels... 

In the real non-equilibrium conditions of a present-day MCFC with very successful electrode reform, the cell electrode reaction, voracious for fuel, consumes the reformer product and favourably influences the reform process. The latter turns out to operate well at 600 °C, compared with about 800 °C in a fired reformer coupled, say, to much less voracious hydrogen separation and storage. In the practical SOFC, 1000 °C at the anode promotes excessively vigorous electrode reform, which leads to a local electrode cold spot. There are also stability considerations (Gardiner, 1996). Hence the contemporary movement towards lower SOFC temperatures, via new ceria electrolytes, and interconnect change from ceramic to steel. A PEFC near Tq, must have a combustion-operated 800 °C reformer, since a Tq electrochemical reform process does not exist in practice. 

Figure 15.12. Electrode structure with two elements of composite structure. 1) The electrode adhesion on the interface towards ihe dense electrolyte is improved by a physical anchoring (YSZ-scalesK and 2> the electrode funciions are divided on two layers taking care of the electrochemical oxidation of hydrogen (ceria) and current collcclion respectively.

Back in 1964, Mdbius and Rohland showed that ceria could work as an anode in an SOFC fuelled with H2 and CO, and shortly after Takahashi et al. described Ceo6Yo.40i 8 and CcoeLao Oi s as being excellent anode materials for SOFC. Since then, a number of studies have been carried out." Cells with a ceria anode may have a performance similar to cells with Ni-YSZ- electrodes in hydrogen at 1000°C. 

Song, Y., Zhong, Q., and Tan, W. (2014) Synthesis and electrochemical behaviour of ceria substitution LSCM as a possible symmetric solid oxide fuel cell electrode material exposed to H2 fuel containing H2S. Int. J. Hydrogen Energy, 39 (4), 1369-1370,... 

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