User research at BESSY II: Graphite electrodes for rechargeable batteries investigated
The tomogram during the charging process shows the spatially resolved changes in the graphite electrode thickness of a rechargeable aluminium ion battery in a discharged and charged state. © HZB
Rechargeable graphite dual ion batteries are inexpensive and powerful. A team of the Technical University of Berlin has investigated at the EDDI Beamline of BESSY II how the morphology of the graphite electrodes changes reversibly during cycling (operando). The 3D X-ray tomography images combined with simultaneous diffraction now allow a precise evaluation of the processes, especially of changes in the volume of the electrodes. This can help to further optimise graphite electrodes.
Published in Advanced Functional Materials (2020); Simultaneous X‐Ray Diffraction and Tomography Operando Investigation of Aluminum/Graphite Batteries; Giuseppe Antonio Elia, Giorgia Greco, Paul Hans Kamm, Francisco García‐Moreno, Simone Raoux, Robert Hahn
DOI: 10.1002/adfm.202003913
Abstract: Rechargeable graphite dual‐ion batteries are extremely appealing for grid‐level stationary storage of electricity, thanks to the low‐cost and high‐performance metrics, such as high‐power density, energy efficiency, long cycling life, and good energy density. An in‐depth understanding of the anion intercalation mechanism in graphite is fundamental for the design of highly efficient systems. In this work, a comparison is presented between pyrolytic (PG) and natural (NG) graphite as positive electrode materials in rechargeable aluminum batteries, employing an ionic liquid electrolyte. The two systems are characterized by operando synchrotron energy‐dispersive X‐ray diffraction and time‐resolved computed tomography simultaneously, establishing a powerful characterization methodology, which can also be applied more in general to carbon‐based energy‐related materials. A more in‐depth insight into the AlCl4−/graphite intercalation mechanism is obtained, evidencing a mixed‐staged region in the initial phase and a two‐staged region in the second phase. Moreover, strain analysis suggests a correlation between the irreversibility of the PG electrode and the increase of the inhomogenous strain. Finally, the imaging analysis reveals the influence of graphite morphology in the electrode volume expansion upon cycling.
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- MAX IV and BESSY II initiate new collaboration to advance materials scienceSwedish national synchrotron laboratory MAX IV and Helmholtz-Zentrum Berlin (HZB) with BESSY II light source jointly announce the signing of a 5-year Cooperation Agreement. The new agreement establishes a framework to strengthen cooperation for operational and technological development in the highlighted fields of accelerator research and development, beamlines and optics, endstations and sample environments as well as digitalisation and data science.
- Michael Naguib is visiting HZB as a Humboldt Research AwardeeProfessor Michael Naguib, from Tulane University in the USA, is one of the discoverers of a new class of 2D materials: MXenes are characterised by a puff pastry-like structure and have many applications, such as in the production of green hydrogen or as storage media for electrical energy. During his Humboldt Research Award in 2025, Professor Naguib is working with Prof Volker Presser at the Leibniz Institute for New Materials in Saarbrücken and with Dr Tristan Petit at HZB.