White Paper Series 2: In Situ X-ray Approaches in Battery Research

Systems for Research is proud to announce the release of a new white paper titled “In Situ X-ray Approaches in Battery Research” by its leading partner, Sigray. 

The paper effectively highlights the development of a suite of groundbreaking lab-based x-ray tools for energy research with performance capabilities approaching that of synchrotron-based approaches. 

When it comes to x-ray techniques for battery development, we often look at four commonly used techniques: 

• X-ray absorption spectroscopy (XAS) to provide electrochemical information such as chemical or valence states, bond length, coordination number 
• Micro X-Ray Fluorescence (microXRF) for elemental composition, migration, and contamination 
• X-ray Diffraction (XRD) to study the crystal structure and bond lengths of battery materials 
• X-ray Microscopy (XRM) for failure analysis and to study structural degradation and particle agglomeration in intact batteries and in operando pouch cells

This 2/4 part of this white paper series dives more into the use of X-ray absorption spectroscopy with Quantum Leap. 

A technique Overview 

MicroXRF is an ultrahigh sensitivity approach for elemental mapping and quantification. X-ray Fluorescence occurs when x-rays excite atoms within a sample, promoting inner shell electrons to the outer shells or emitting them from atoms.

This relaxation produces an x-ray. Because the distances between outer shells and inner shells is characteristic to each element, measurement of the x-ray energies emitted by the sample gives not only the elements contained within the illuminated region, but also the quantity.

System Overview

Sigray AttoMap microXRF is truly unbeatable as it provides unprecedented sensitivity to detect heavy and even light elements (e.g., C, O, N) that are too low concentration to be measured using electron-based techniques such as SEM-EDS and EPMA or other microXRF systems.

Sigray’s patented x-ray energy tunable source and high efficiency double paraboloidal x-ray optics allow the instrument to provide fast, non-destructive chemical mapping at <5 µm resolution and bring the acquisition times down to 2 ms per point. A major advantage of the Attomap is its ability to tune X-ray incident energy to elements of interest to maximize fluorescence cross section. This ability to switch energy can increase sensitivity > 1000X as seen in the figure below. 

Figure 1: Sigray AttoMap features a patented x-ray source with multiple x-ray targets (each target produces a different x-ray spectra). Arsenic from the same sample is shown using two different x-ray targets: tungsten and molybdenum to illustrate the major gains in sensitivity possible.

Application in Battery Research 

Attomap provides high sensitivity detection levels down to sub-ppm levels for transition elements commonly used in battery research. 

Unique to the AttoMap is its strength in trace-level detection (e.g., sub-0.01%) of important low Z elements such as Al, Mg, Na, F, S, P, and organics (C, O, N). This is achieved using a tilted goniometer stage and a high vacuum enclosure with 10E-5 Torr. The ability to tilt the sample stage in the Attomap also allows elemental analysis to vary from deep to shallow interaction volumes.

AttoMap’s High Sensitivity: A Key Advantage  

• Monitor and track cross contamination such as Fe particles during battery manufacturing and quality control (QC) processes.
•  Quantify the migration of transition elements across electrodes as a function of the charging cycle.
• Inspect chemical composition and the ratio of elements in NMC batteries.

Sigray has developed a correlative workflow to first identify the location of potential impurities using transmission X-ray microscopy, followed by AttoMap microXRF to identify the chemical composition of these impurities.

Systems for Research (SFR) is a proud partner of Sigray, the leading name in X-Ray Microscopy and we are diving into the potential of this suite of spectroscopy and laboratory tools in a four-part series. Stay tuned as we dive into part ¾ of this series as we discover more about X-ray Microscopy with EclipseXRM and Apex XCT.