CMSP Webinar (Atomistic Simulation Seminar Series) 8 June at 11:00, Dr. Mohsen Sotoudeh

[CMSP Seminars Secretariat]

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Atomistic Simulation Webinar Series
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Zoom link to advance registration:

https://zoom.us/meeting/register/tJ0tce-trjIpH9Yfv6mZszhv-H6BaglMtO5c


** * * Wednesday, 8 June 2022 at 11:00**CET* * **


Speaker:*  Dr. Mohsen Sotoudeh *(Ulm University, Germany)

Title:** *Understanding ion mobility mechanism using descriptors and 
scaling relations in solid crystals* *
*
Abstract:

In the area of sustainable energy storage and conversion, super ionic 
conductors have been attracting considerable attention due to their 
potential utility for electrochemical devices such as electrodes and 
solid electrolytes. Through density functional theory investigations, we 
have derived a descriptor for the ion mobility just based on easily 
accessible observables: ionic radii and oxidation states of the 
migrating cations and the anions of the host lattice, and the difference 
in their Pauling electronegativity. A statistical compressed-sensing 
approach using the sure-independence screening and sparsifying operator 
SISSO has been applied to verify our proposed descriptor. We find that 
the migration barriers are connected through linear scaling relations 
upon variation of either the cation chemistry of the charge carrier or 
the anion chemistry of the host lattice. This demonstrates the strong 
predictive power of the descriptor, which should accelerate the 
discovery of materials with improved migration properties in 
electrochemical energy storage and conversion ^[1] .

We address the ionic conductivity in spinel host materials which 
represent a promising class of cathode and solid-electrolyte materials 
in battery technology. Based on the descriptor, we demonstrate that 
ionic mobility can be increased through the incorporation of rather 
electronegative cations from the 4d and 5d series. For instance, the 
conductivity of Mg2+ in Mg(Ir/Rh)2O4 materials compares well with those 
of Li+ in fast Li-ion conductors, such as Garnets. We will highlight the 
critical role trigonal distortions play in the ion mobility and show 
that it is the competition between coordination and bond length that 
governs the Mg site preference in ternary spinel compounds. This can 
only be understood by considering covalent interactions revealing that 
purely ionic interactions are not sufficient to understand mobility in 
crystalline battery materials. Furthermore, our calculations suggest a 
more important role of anionic redox in sulfide and selenide spinels 
than in oxide spinels. ^[2] We show that a fundamental understanding of 
the chemical interactions within transition metal chalcogenides is 
instrumental in offering guidelines aimed to increase the ion mobility 
in post Li-ion technologies resulting in a descriptor that allows to 
predict migration barrier energy.

Literature:

^[1] M. Sotoudeh and A. Groß JACS Au 2022, 2, 463–471

^[2] M. Sotoudeh, M. Dillenz, A. Groß, Adv. Energy Sustainability Res. 
2021, 2, 2100113.


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