Berlin 2024 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 24: Focus Session: Battery Materials – Ion Transport, Impurity Effects and Modelling (joint session KFM/MM)

KFM 24.3: Talk

Thursday, March 21, 2024, 10:20–10:40, EMH 225

Rhombohedral (R-3) Prussian white cathode material: An ab-initio study — •Sebastian Baumgart¹, Mohsen Sotoudeh¹, and Axel Groß^1,2 — ¹Institute of Theoretical Chemistry, Ulm University, Ulm, Germany — ²Helmholtz-Institute Ulm (HIU) for Electrochemical Energy Storage, Ulm, Germany

The demand for efficient and sustainable cathode materials for alternative battery chemistries is ever more increasing. Prussian Blue analogues (PBAs) exhibit a long cycling life and a high rate capability, which makes them a promising cathode material for next-generation battery technologies. Notably, Prussian White (PW) exhibits a phase transition at high sodium and low vacancy content, transitioning to a rhombohedral (R-3) phase.

However, the detailed exploration of the rhombohedral modification and its electronic structure remains incomplete. In this study, we provide insights into why the rhombohedral structure manifests itself only at high sodium contents, employing atomistic first-principles calculations.

Our findings reveal the stabilization of the rhombohedral structure by sodium atoms. Additionally, we elucidate the changes in the sodium ion minimum energy position during the phase transition and analyze the sodium migration barrier within the cubic and rhombohedral phases, offering a comprehensive theoretical assessment of its viability as a battery material.

Keywords: Cathode material; Density functional theory; Ion mobility; Na-ion battery; Prussian white