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Electron Microscopy Solutions

Automated 3D EDS with Talos

Best EDS data, seamless automation, stunning results.

The ability to perform compositional analysis and visualize the resulting chemical maps in 3D is essential to characterize the true elemental structure and distribution, ultimately delivering new insights into the structure-function relationship of modern nanomaterials.

Advanced Materials Characterization

Scientists and engineers studying a vast variety of materials, such as metals, catalysts, batteries, polymers, ceramics and composites, need nanoscale materials characterization in three dimensions. Full 3D characterization includes the need for chemical as well as imaging data, making 3D EDS an indispensable technique in the new world of materials research. For the highest quality results, instrumentation with dynamic high-resolution imaging capabilities as well as fast and quantitative data acquisition is therefore required. The combination of flexibility in sample imaging optimization, the ability to easily utilize different imaging acquisition schemes, such as TEM and STEM, and the fast and highly sensitive collection of the elemental distribution data are prerequisites for capturing the real 3D structure of nanomaterials.

In this application note, we show the importance of having fast, clean & high yield EDS capability to fully characterize the 3D chemical composition of a variety of nanomaterials. The EDS tomography application use cases presented cover a wide range of resolution and field of view - ranging from a few hundred down to a few nanometers. To study the nanomaterials, we employed the new FEI Talos™ 200 kV analytical FEG S/TEM, which includes the patented FEI Super-X integrated, automated EDS system with four silicon drift detectors (SDDs) for superior sensitivity and mapping capabilities. Visualization and reconstruction was done using FEI Inspect 3D and Avizo® software.

In the following application examples, researchers made use of the automated 3D EDS capabilities of the Talos, enabling them to pre-select a range of parameters in the operating software, e.g. mapping conditions (either selecting high throughput, high quality or a balanced combination of both as the most important criterion for the dataset), drift compensation, and detector parameters, in addition to the ability to set conditions for auto focus and auto tilt. This level of automation means that the operators set up the EDS tomography and then left the system unattended for the complete data acquisition process.

Application Example 1: Focused Ion Beam (FIB) prepared battery anode material

This example shows the large field of view EDS tomography of a FIB prepared battery anode material consisting of Nickel, Cobalt, Aluminum, and Carbon Black. Also called NCA batteries, these batteries are increasingly important in electric powertrains and in grid storage. NCA batteries are currently being investigated by the automotive industry for use in electrical vehicles due to their high energy and good lifespan. In this use case, besides locating the distribution of the individual elements Nickel, Cobalt, and Aluminum, it was particularly important to identify the distribution of the Carbon. The digital z-slicing of the STEM image and the elemental maps clearly show the location of the individual grains. The second z-slicing sequence shows the exact position of the Carbon (in red) relative to the other elements. The accompanying 3D EDS maps of Nickel, Cobalt, and Aluminum show the distribution in space for every constituent element and also the location of Carbon within the material.

Digital z-slicing of STEM image and elemental maps of Cobalt, Aluminum, and Nickel without Carbon.
Digital z-slicing of STEM image and elemental maps of Cobalt, Aluminum, and Nickel with Carbon.
EDS tomography of Carbon Cobalt.
EDS tomography of Carbon Aluminum.
EDS tomography of Carbon Nickel.

Application Example 2: Vehicle aged automotive catalyst

The second application example shows a large field of view EDS tomography study of a vehicle aged catalyst. Automotive catalysts use Platinum, Rhodium, and Palladium to speed up chemical reactions of pollutants such as nitrogen oxide, carbon monoxide, and hydrocarbons, to create non-toxic emissions. By using nanoparticles of the precious metals instead of larger particles, less metal is needed to produce the same surface area over the ceramic base of the catalyst. Exhaust heat can cause the nanoparticles to migrate over the surface of the ceramic bead, agglomerating into larger particles. This reduces the overall surface area of the metal, reducing the converter's efficiency. The agglomeration problem is believed to be solved by embedding the precious metal nanoparticles into the ceramic in fixed positions. Therefore, in this use case, it was especially important to locate the distribution of the relatively small Palladium particles (in red). The STEM image clearly reveals the location of the Palladium particles on the surface and within the sample. By adding colors to the elemental maps and tomography, the distribution of the Palladium nanoparticles becomes visible relative to other elements.

STEM and EDS tomography showing the distribution of the Palladium particles (red) relative to other elements of the vehicle aged catalyst material.

Application Example 3: Nanotubes

The third application example shows nanotubes used as electrode material for Na-ion and Li-ion batteries. The segregation of Zinc is not very well known during the synthesis. The elemental maps and EDS tomography, however, very clearly reveal the distribution of the Zinc relative to the other elements. It also becomes evident that there is almost no concentration of Zinc in the straight nanotubes.

STEM image of P-Zn-In nanotubes.
EDS tomography of P-Zn-In nanotubes. Sample Courtesy of Dr. Reza Shahbazian Yassar, Michigan Tech University.

Application Example 4: Core-shell nanoparticles

The fourth application example shows an EDS tomography study of Ag-Pt core-shell nanoparticles with elemental resolution down to a few nanometers. Ag cores are shown in the false color of red, covered by green-colored Pt shells, only a few nanometers in thickness. The EDS tomography technique makes visible the pores that partially expose the cores. In this use case, it was of great importance to determine if the Pt layer was continuous or possessed pores. This determination could not be made from a single 2D EDS map; therefore, EDS tomography in three dimensions was employed.

Digital slice of the reconstructed Ag-Pt core shell nanoparticle volume. Sample courtesy Prof. Yi Ding and Prof. Jun Luo, Center for Electron Microscopy, Tianjin University of Technology.
Segmented surface rendering of nanoparticles with elements present: Ag core, Platinum shell (to increase visibility, the Platinum shells have been colored semitransparent).

The data sets were acquired using the FEI Talos 200kV analytical FEG S/TEM (Scanning Transmission Electron Microscope). The Talos F200 has been optimized for EDS analysis in multiple dimensions for a wide range of materials science applications. The high signal to background ratio, sensitivity to low concentration and light elements, low spurious peaks and low sensitivity tilt combined with the ease of use and high resolution imaging capabilities of the Talos enable it to deliver the cleanest EDS spectra in the shortest time.

Designed from the ground up to be an entirely new TEM experience, the FEI Talos F200 accelerates nanoscale discovery for everyone by delivering high-quality images and fast analytical data acquisition-all from an easy to use, automated operating platform. The Talos combines high-resolution, high-throughput S/TEM imaging with fast, precise, and quantitative energy dispersive X-ray (EDS) analysis to deliver advanced analytical performance. The new TEM is available with FEI's highest brightness electron source and latest EDS detector technology to provide high-efficiency detection of low-concentration and light elements, along with FEI's EDS tomography. Excellent performance at lower accelerating voltages enables the use of lower beam energies to reduce sample damage on delicate materials. The Talos platform is completely digital, allowing for remote operation. It also enables the addition of application-specific detectors or sample holders for dynamic experiments. With enhanced automation and ease-of-use, the Talos is especially well-suited for multi-user laboratories as well as the individual investigator environment.

FEI Talos F200 S/TEM features:

-          Fast, precise 2D and 3D chemical analysis, with dynamic EDS at high temperatures

-          High-throughput, high-resolution multichannel STEM and TEM imaging

-          Remote control with precise and fast navigation for versatile (in situ) applications