Battery research at DESY What X-rays reveal about the inner workings of batteries

What happens inside a battery? How does its chemical composition change during the degradation and aging processes? And what alternatives might there be to the types of battery used today? X-ray analysis techniques allow us to examine these very questions under real-life conditions. “When it comes to battery research, industry and science are dealing with the same issues,” says Alexander Schökel, Researcher at DESY and jointly responsible for beam guidance for powder diffraction and total dispersion at the PETRA X-ray radiation source. These issues include improved efficiency, extended service life, further development and possible alternatives to today’s lithium-ion batteries. All questions that are also being investigated at DESY.

The benefit of high-energy X-rays like those used on the X-ray radiation source PETRA III at DESY is that the investigations are non-invasive. The spectrum of analytical methods allows us to address various research questions. For example, a working group examined the ‘18650’-type battery that is used in electric cars, as well as in notebooks and drills. Researchers analysed the behaviour of the lithium in these cells during charging and discharging with an accuracy of up to 20 micrometres. The results showed irregular lithium concentrations around the contacts, which adversely affect efficiency and performance. Based on these findings, design changes can be implemented to optimise the potential of the cells. Further investigations by the team focus on the service life of the cells following hundreds of charging cycles; these measurements provide a live insight, as they can be recorded during the respective processes. Experiments can also be conducted under various conditions, such as at low or high temperatures, for example, as well as under increased pressure.  

In addition to optimising standard batteries, teams at DESY are also working on new concepts, including developing sustainable batteries made from renewable natural materials. One such example is peptides, organic amino acid compounds obtained from cereals. Electrically conductive properties of cereal peptides are used to store and release energy. These peptide batteries are still in the very early stages of development; the long-term vision is to be able to produce an eco-friendly alternative to conventional batteries. These organic batteries could even be implanted in our bodies to power medical devices such as pacemakers and brain implants, or to operate smart patches to monitor vital functions.

Not only companies but also other research groups use the analytical methods at PETRA III. For example, a research group from Helmholtz-Zentrum Berlin examined sodium-ion batteries at DESY and other locations to see how the cathode material can be enriched and with which elements in order to improve the stability of these batteries.