Ceria electrolytes current density

Tsai et al. (1997) reported building soUd-oxide fuel cells with an electrolyte of yttrium-doped ceria that was 4 to 8 p,m thick. A thin layer (1 to 1.5 p,m) of a second electrolyte, of the YSZ type, was deposited between the electrolyte and the anode to eliminate the influence of electronic conductivity of the electrolyte. A cell having this bilayer electrolyte had an OCV of 98% of the theoretical EMF, which shows that there is no effect of the electronic component of conduction (without the second YSZ electrolyte, the OCV was only 50% of the theoretical value). At 600°C the electrolyte had a resistivity of 0.25 cm. At a current density of 400 mA/cm, the cell voltage was 0.4 V. The maximum energy density was 210 mW/cm. At 550°C, the resistivity of the electrolyte was 0.45 cm ... 

Doshi et al. (1999) used an electrolyte of ceria-doped gallate (CeGO) 30 p,m thick. In the cell, a two-phase cathode 250 p,m thick was used that consisted of a cermet of 45 to 55% silver and electrolyte material in the form of yttria-doped bismuth oxide (YDB). An Ni-CeGO cermet served as the anode. At a working temperature of 500°C and a ceU voltage of 0.6 V, the current density was 100 mA/cm at a cell voltage of 0.4 V, the current density was 3(K) mA/cm. It is interesting to note that in this cell, the contributions of the ohmic resistance of the electrolyte (0.7 cm ) and of cathode polarization (0.6 cm ) to the... 

Doped and undoped ceria exhibit ionic and electronic conduction at low oxygen partial pressures. Ce" " gets reduced to Ce ", which is the main cause for mechanical failure due to lattice expansion (for low oxygen partial pressure). The electrolyte/electrode interface may be delaminated due to the formation of cracks. When 40-50% of Ce" " ions are substituted with Gd " ions (Ceo.6Gdo.40i.8-CGO), then a balance between lattice parameters and conductivity with the YSZ electrolyte and an anchoring YSZ layer provides the ability to resist the thermal expansion mismatch. Uchida and co-workers obtained the electrocatalytic activities for the SDC and Yttria doped Ce02 (YDC) for the electrodes sintered at 1150 and 1250°C. The current density of 0.2-0.25 PJcvc is observed for SDC and YDC anodes,... 

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