Using the new NAPXAS instrument at the Karlsruhe Research Accelerator (KARA), researchers at the Karlsruhe Institute of Technology (KIT) and the University of Münster aim to observe at the molecular level exactly how batteries charge and discharge. By making liquids accessible for synchrotron research with soft X-rays, NAPXAS provides unique insights into the processes at work in batteries.
Synchrotrons are particle accelerators that emit electromagnetic radiation such as soft X-rays. Synchrotron radiation enables insights into the internal structure and workings of materials, so it plays an important role in the development of advanced technologies. Soft X-rays (with wavelengths around one to two nanometers) are ideal for research on electrochemical storage systems for the energy transition – but their use has been limited so far: they require a vacuum environment. “In a complicated process performed under inert gas, battery material had to be extracted, dried, affixed to suitable sample holders, and then – without contamination by air or moisture – transferred into a vacuum chamber for the measurements with soft X-rays,” says Dr. Peter Nagel from KIT’s Institute for Quantum Materials and Technologies (IQMT). “To analyze entire charging cycles, these steps had to be performed on hundreds of differently prepared batteries at various stages of their cycles.”
Now that is bound to change with a new instrument called NAPXAS (Near Ambient Pressure X-ray Absorption Spectroscopy), which has been implemented at IQMT’s soft X-ray analytics facility WERA at the Karlsruhe Research Accelerator’s (KARA’s) KIT Light Source. “With NAPXAS, we can perform spectroscopic investigations of energy conversion and aging processes in batteries under more or less standard wet chemistry conditions, and we can do that live while the batteries are in use,” says Nagel, who is heading KIT’s work on the project.
New Survey of Lithium Ion Technology’s Limits
NAPXAS will be put to use for the first time in the LimLi (which stands for overcoming the LIMitations of LIthium-ion batteries) research project by the University of Münster. Dr. Karin Kleiner, who heads the corresponding research activities at the university’s battery research center MEET (Münster Electrochemical Energy Technology), says: “We want to understand what limits the energy storage capacity of lithium-ion batteries at the atomic level so that we can overcome those limits. With a combination of theoretical and innovative experimental methods, we can gain unique insights into energy storage processes. Our goal is to develop new and more efficient ways of storing and converting energy by systematically changing the active sites in battery materials.”
Available for International Research
The new apparatus is currently in a test phase, undergoing commissioning. The synchrotron radiation needed for its measurements will be supplied by KARA, which is operated as an accelerator test facility and as the KIT Light Source by the Institute for Beam Physics and Technology. After completion of this test phase, plans call for researchers worldwide to have access to NAPXAS and WERA through the Karlsruhe Nano Micro Facility, a high-tech platform for research on functional materials in the micro- and nanometer range. Funding for NAPXAS has been provided by Germany’s Federal Ministry of Education and Research through the LimLi research project.
More about the KIT Energy Center
Detailed caption: Preparing for initial test measurements, Dr. Peter Nagel, Dr. Karin Kleiner and Amir Ghiami (left to right) feed the beam into the new NAPXAS instrument at the WERA beamline at the KIT Light Source. (Photo: Amadeus Bramsiepe, KIT)
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