Editing Solid oxide fuel cell (section)

===Ohmic polarization===

Ohmic losses in an SOFC result from ionic conductivity through the electrolyte and electrical resistance offered to the flow of electrons in the external electrical circuit. This is inherently a materials property of the crystal structure and atoms involved. However, to maximize the ionic conductivity, several methods can be done. Firstly, operating at higher temperatures can significantly decrease these ohmic losses. Substitutional doping methods to further refine the crystal structure and control defect concentrations can also play a significant role in increasing the conductivity. Another way to decrease ohmic resistance is to decrease the thickness of the electrolyte layer.

====Ionic conductivity====
An ionic specific resistance of the electrolyte as a function of temperature can be described by the following relationship:<ref name="Milewski J, Miller A. 2006 396-402"/>

:<math>r_1 = \frac{\delta}{\sigma}</math>

where: <math>\delta</math> – electrolyte thickness, and <math>\sigma</math> – ionic conductivity.

The ionic conductivity of the solid oxide is defined as follows:<ref name="Milewski J, Miller A. 2006 396-402"/>

:<math>\sigma = \sigma_0\cdot e^\frac{-E}{R\cdot T}</math>

where: <math>\sigma_0</math> and <math>E</math> – factors depended on electrolyte materials, <math>T</math> – electrolyte temperature, and <math>R</math> – ideal gas constant.