The research neutron source Heinz Maier-Leibnitz (FRM II) is a central scientific institute of the Technical University of Munich (TUM). The cooperation between the TUM, Forschungszentrum Jülich and Helmholtz Zentrum Geesthacht (HZG), with the collaboration of the Max Planck Society and nine further University groups, is known as the “Heinz Maier-Leibnitz Zentrum” (MLZ). Various working groups of the cooperation partners of the MLZ are conducting research in various fields of which materials science is one.
In collaboration with HZG and TUM, the Materials Science Lab serves as a laboratory for complementary analytics and sample preparation. It is equipped with several analytical instruments. Among their impressive range of analytical instruments is a Malvern Panalytical Empyrean X-ray diffractometer with Cu and Mo X-ray source which is mainly being utilized for battery research.
The addition of the GaliPIX3D detector on the Empyrean XRD platform allows for advanced studies of thick samples like batteries. It is designed for applications - such as in situ and in operando measurements of battery cells - requiring the use of hard X-radiation.
In operando XRD is a must-have technique for battery research as it is important to understand the stability of battery materials when cycled in a battery cell. Many materials look promising in terms of high energy density and discharge capacity but undergo a rapid capacity decrease upon cycling. Most times the capacity decay can be traced back to the structural stability of these materials during charge-discharge cycles. X-ray diffraction (XRD) can be used as an analytical technique to monitor important parameters like the formation of multiple phases and changes in the crystallite size.
‘With the GaliPIX3D detector, we observe a tremendous increase of the measurement speed’ says Dr. Stefan Seidlmayer of the Heinz Maier-Leibnitz Zentrum at the Technical University of Munich. ‘Due to the larger detector window, this is achieved even for Cu-radiation. The speed up we obtained was roughly a factor of three, of course when comparing same diffracted intensity levels and statistics’ he continues.
For Mo-radiation the speed up is even larger, since the increased detection efficiency also leads to an improved intensity. In effect, the speed up for Mo is roughly a factor of 5, when looking at the same intensity and quality levels of the diffraction patterns. ‘This is significant for us, because it enables nearly real-time operando diffraction of single reflections for our Li-ion battery cells in our Mo-radiation setup. Alternatively, we can also bring down the measurement time for a full pattern (7-49 °2 Theta to approximately 10 minutes). With X’Celerator we were needing roughly 1 hour for a full angular scan (with the same quality and intensity levels) - thus significantly limiting our operando capabilities.’
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