As of 2026 and with the beginning of the new funding period of the Cluster of Excellence POLiS, the GS-EES will transition into an EES Academy. This EES Academy will not only continue all aspects established within the GS-EES – which will remain an integral part of the EES Academy – but also extend its offers to postdoctoral and junior faculty scientist.

Around 25 researchers from the POLiS Cluster of Excellence and the Graduate School Electrochemical Energy Storage (GS-EES) had the great opportunity to visit the Center for Solar Energy and Hydrogen Research (ZSW) in Ulm – a key player in applied battery research and technology transfer in Germany.

POLiS doctoral researcher Till Ortmann was awarded a poster prize at the 5th International Symposium on Sodium Batteries in Berlin.

POLiS doctoral student Till Ortmann was awarded a poster prize at the 5th International Sodium Battery Symposium in Berlin.

As part of the 5th International Sodium Battery Symposium, which took place from 23 to 25 September 2025 in Berlin, the organizers Dr. Gustav Gräber and Prof. Dr. Philipp Adelhelm awarded the three best posters with a prize. Till Ortmann is a POLIS doctoral researcher t in the group of Prof. Jürgen Janek at Justus Liebig University Giessen and received a poster prize for his work on t he microstructure elucidation of deposited Na in Na solid-state batteries. The Na-Battery Symposium, which is now being held for the 5th time, is registering a steadily growing number of participants. While 10 people came together for the first meeting, this year in Berlin over 330 participants were present, which clearly emphasizes the importance of Na batteries.

Till Ortmann is also member of the Gradute School "Electrochemical Energy Storage" (GS-EES).

The picture shows from left: Dr. Gustav Gräber (Humboldt University Berlin), Chantal Glatthaar (Justus Liebig University Giessen), Zhenyu Guo (Imperial College, UK), Till Ortmann (Justus Liebig University Giessen), Prof. Dr. Philipp Adelhelm (Humboldt University Berlin).

Prussian Whites (PW) have gained attention for their potential application as high energy density cathodes in Na-ion batteries. However, the rhombohedral phase of this compound still remains elusive. This study addresses the electronic and structural properties of the rhombohedral host material, as well as its ionic conductivity. Using periodic density functional theory calculations, we identified the critical factors that determine the sodium-ion site preference and their ionic mobility. Specifically, the significant role of octahedral tilting and trigonal distortions of the structure have been highlighted.