Single with coplanar electrodes

Figure 40 gives an electrical solution for the single-cell detection with coplanar electrodes. Such technique is easy to implement but has poor sensitivity due to noneffective using of distorted electric field between the electrodes. 

Miniaturization limits for single-chamber micro solid oxide fuel cells with coplanar electrodes. J. Power Sources, 194 (2), 941-949. 

Figure 41 gives an impedimetric setup for single-ceU detection with two pairs of parallel electrodes [7]. Though the electrode system is more complicated in comparison with coplanar placement of electrodes in Fig. 40, this solution is much more resultful. The sensitivity is increased because of more targeted and homogeneous electrical field between the upper and lower electrodes, and thanks to effective compensation of electrode polarization. 

The coplanar fuel ceU design is used primarily for fuel cells with a mixed-reactant supply. In this design both selective electrodes (anodes and cathodes) are situated on the same surface of the electrolyte (ion-conducting membrane, matrix filled with liquid electrolyte, or solid electrolyte). This surface also contacts the reactant mixture. Such an electrolyte is said to be single-faced. This is in contrast to the conventional MEAs used for almost all varieties of fuel cells, in which the electrolyte is dual-faced, contacting the anode and the fuel on one side and the cathode and the oxidizer on the other side. 

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