Quantitative mapping of lithium in a scanning electron microscope

Instruments used

We bring together the OnPoint™ detector and EDAX^® Octane Elite Super EDS system to map lithium in the scanning electron microscope (SEM).

Background

Lithium-containing compounds and alloys are critical in our efforts to meet energy reduction commitments. Undoubtedly, we have seen enormous strides in the development of these materials but perhaps, what is even more impressive is that this has largely been achieved without a robust method to reveal or quantify the distribution of lithium at the microscale. A quantitative method to map lithium in bulk materials remains one of the holy grails for microanalysts as energy dispersive x-ray spectroscopy (EDS) is largely ineffective for elements with an atomic number lower than 4. However, quantification of Li in the SEM was demonstrated recently using a composition by difference method based on EDS and quantitative backscattered electron imaging (qBEI) [J.A. Österreicher et al., Scripta Materialia 194 (2021) 113664]. We extend the composition by difference method to generate quantitative, spatially resolved elemental maps of a MgLiAl alloy.