The purpose of this SOP is to define a standard set of definitions, metrics, units, and conventions for high temperature electrolysis (HTE). The goal is to ensure that the literature is consistent from research group to research group, and data is reported in similar formats, such that results can be compared on a similar basis. This SOP is a first draft and is intended to be revised and added to in collaboration with the HTE community.

The purpose of this SOP is to describe a method for electrochemical impedance spectra (EIS) measurement of single solid oxide cells. By measuring the impedance response to frequency change, kinetics about ohmic and electrolyte/electrode interface transport with different time constants can be separated and attained. 

The purpose of this SOP is to describe best practices for evaluation of the electrode polarization resistance for symmetrical solid oxide cells using electrochemical impedance spectroscopy technique. It applies to common oxide materials which are used as oxygen evolution electrode (anode) in SOEC.

The purpose of this SOP is to describe the method for testing electrode/electrolyte-supported solid oxide electrolysis cells with nickel-based hydrogen electrodes. The best practice recommendations apply to single cells for the performance evaluation of materials.

The purpose of this procedure to identify if any leaks are present in the system.

Measurement of the linear thermal expansion of solid materials can provide useful information regarding the compatibility of various materials during device fabrication and device operation (especially in regard to operation involving thermal cycles).

Measurements of the density of sintered materials provide useful information regarding the suitability of a given processing or fabrication approach to achieve the level of density/porosity required for a given material application.

The purpose of this SOP is to describe a method for measurement of ionic and electronic conductivity in mixed ionic electronic conductor ceramics for intended use in solid oxide cells. The method is based upon the relationship between concertation of charge carriers (ions, electrons or holes) and oxygen partial pressure of the atmosphere around the specimen. 

The purpose of this SOP is to describe a method for evaluation of ionic transference number in mixed ionic electronic conductor ceramics intended for use in solid oxide cells. In this method, different partial pressures of gases are maintained over the two sides of ion conductor solid oxide membrane and an ionic transference number is the ratio between the measured voltage and the Nernst voltage. 

When investigating new materials for solid oxide cells (SOC) (electrodes, electrolytes, coatings), conductivity measurements are an important part of the materials characterization profile. Conductivity can be measured as a function of temperature and under controlled oxygen partial pressures (pO2) or gas compositions of interest.