Ex Situ Spatial Characterization Capabilities to Support Cell Component Integration and Scaling Studies


National Renewable Energy Laboratory (NREL)

Capability Expert

John Perkins, Michael Ulsh



Node Readiness Category

2: Low-Temperature Electrolysis (LTE)
2: Photoelectrochemical (PEC)
3: High-Temperature Electrolysis (HTE)
3: Solar Thermochemical (STCH)


NREL has performed materials discovery for inorganic, semiconductor-based materials for research in photovoltaics for 15 years, including past and current EFRCs in this area. As a result, extensive mapping tools have been developed for the ex situ evaluation of active layers, including techniques for composition, structure, surface properties and microscopy. Many of these techniques, including mapping x-ray fluorescence (XRF), are useful for hydrogen production active layers, and can be leveraged for HydroGen. In addition, NREL's FCTO-funded Manufacturing R&D project has developed in-line mapping tools specifically designed and validated for the properties and functionality of cell materials and active layers, including optical and active thermographic methods for surface morphology, and thickness and loading uniformity. These tools can be applied, either in an in-line or off-line configuration, for evaluation of both ink properties and deposition process conditions for new hydrogen generation cell materials.

Capability Bounds‎

These are all laboratory-scale capabilities with no pertinent bounding limitations.

Unique Aspects‎

These analytical characterization tools are not unique. However, NREL has adapted these standard techniques to enable mapping of active layers or devices. The mapping techniques developed by NREL's manufacturing R&D project are unique, including some aspects that are covered by intellectual property.


There are no pertinent use limitations.


Development of hydrogen generation cell compositions and structures will require capabilities and methodologies to perform rapid ex situ characterization and mapping of critical electrode properties. This would enable accelerated evaluation of composition and properties of cell materials as well as process parameters for optimal uniformity, performance and durability.


Figure 1. NREL's proprietary optical reflectance mapping testbed

Figure 2. NREL high-throughput ex situ mapping. In this case, absorption mapping data of CoO/ZnO/NiO gradient where the metals composition was determined by XRF mapping.

Figure 3. Example of mapping of matrixed electrode: Pt loading design (left), thermographic imaging of reactive excitation response proportional to loading (center), and XRF line scan along blue line in left image (right)


1. "Applying Infrared Thermography as a Quality-Control Tool for the Rapid Detection of Polymer-Electrolyte-Membrane-Fuel-Cell Catalyst-Layer-Thickness Variations," N. V. Aieta, P. Das, A. Perdue, G. Bender, A. Herring, A. Weber, M. Ulsh; J. Power Sources, 211, p. 4, 2012.
2. Rupnowski, P.; Ulsh, M.; Sopori, B. (2015). "High Throughput and High Resolution In-line Monitoring of PEMFC Materials by Means of Visible Light Diffuse Reflectance Imaging and Computer Vision." PowerEnergy 2015-49212.