Batteries without critical raw materials

With operando techniques, it is possible to observe how solvated ions embed themselves in batterie electrodes. This might help to develop alternative batteries.

With operando techniques, it is possible to observe how solvated ions embed themselves in batterie electrodes. This might help to develop alternative batteries. © G. A. Ferrero

The market for rechargeable batteries is growing rapidly, but the necessary raw materials are limited. Sodium-ion batteries, for example, could offer an alternative. A joint research group from HZB and Humboldt-Universität zu Berlin has investigated new combinations of electrolyte solutions and electrode materials for this purpose.

"In contrast to lithium-ion batteries, which are based on the storage of lithium ions in the positive and negative electrodes of the battery, we are working on the one hand with sodium ions, as they also occur in cheap table salt. On the other hand, we store the sodium ions together with their solvate shell, i.e. solvent molecules from the electrolyte solution that separate the two electrodes. This makes it possible to realise completely new storage reactions," explains Prof. Philipp Adelhelm, who heads the research group "operando battery analysis", which was jointly founded by Humboldt University and Helmholtz-Zentrum Berlin in 2020.

The storage of ions when accompanied by their solvation shell in a crystal lattice is referred to as co-intercalation. Up to this point, this concept was limited to the negative electrode of the sodium-ion battery. Now the researchers around Adelhelm have succeeded in extending the concept to the positive electrode of the battery. Dr. Guillermo A. Ferrero, first author of the publication, explains: "With titanium disulphide and graphite, we have for the first time combined two materials that absorb and release the same solvent during charging and discharging of the battery”. The scientists could observe changes in the material during charging and discharging via operando measurements performed in the X-Ray Core Lab at HZB on the LIMAX 160. This helped them to assign the co-intercalation mechanism inside the battery. They could then use this new knowledge to realise a battery with two electrodes that both rely on reversible co-intercalation of solvent molecules.

“We are still in the early stages of understanding the implications of the co-intercalation batteries. But there are a few possible advantages we can envision”, Dr. Katherine A. Mazzio, HZB, explains: The process of co-intercalation could improve upon efficiency by enabling better low temperature performance. It could also be utilised to improve upon alternative cell concepts such as using multi-valent ions instead of Li+ or Na+ storage that are particularly sensitive to the solvation shell.”

Note: This project received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. [864698], SEED).

HU Berlin/ arö


You might also be interested in

  • BESSY II: How pulsed charging enhances the service time of batteries
    Science Highlight
    08.04.2024
    BESSY II: How pulsed charging enhances the service time of batteries
    An improved charging protocol might help lithium-ion batteries to last much longer. Charging with a high-frequency pulsed current reduces ageing effects, an international team demonstrated. The study was led by Philipp Adelhelm (HZB and Humboldt University) in collaboration with teams from the Technical University of Berlin and Aalborg University in Denmark. Experiments at the X-ray source BESSY II were particularly revealing.
  • Fuel Cells: Oxidation processes of phosphoric acid revealed by tender X-rays
    Science Highlight
    03.04.2024
    Fuel Cells: Oxidation processes of phosphoric acid revealed by tender X-rays
    The interactions between phosphoric acid and the platinum catalyst in high-temperature PEM fuel cells are more complex than previously assumed. Experiments at BESSY II with tender X-rays have decoded the multiple oxidation processes at the platinum-electrolyte interface. The results indicate that variations in humidity can influence some of these processes in order to increase the lifetime and efficiency of fuel cells. 
  • Best Innovator Award 2023 for Artem Musiienko
    News
    22.03.2024
    Best Innovator Award 2023 for Artem Musiienko
    Dr. Artem Musiienko has been awarded a special prize for his groundbreaking new method for characterising semiconductors. At the recent annual conference of the Marie Curie Alumni Association (MCAA) in Milan, Italy, he received the MCAA Award for the best innovation. Since 2023, Musiienko has been carrying out his research project with a postdoctoral fellowship from the Marie Sklodowska Curie Actions in Antonio Abate's department, Novel Materials and Interfaces for Photovoltaic Solar Cells (SE-AMIP).