The success of the rechargeable Li-ion battery is apparent to everyone, as most people in the Western world own at least one device powered by this technology. Now, this battery type is on the verge of becoming even more relevant with the transition from vehicles using a combustion engine to the more environmentally friendly battery-driven vehicles.
On the other hand, everyone is also aware of the challenges facing this technology in the form of low capacity, long charging times, capacity fading and expensive replacements. Scientists are working hard on all these issues using state-of-the-art experimental techniques to understand all details of the battery. In the quest to understand the ionic structure of battery components, that is the spatial arrangement of the ions that make up the material, the use X-rays to see inside the battery has been the dominant technique for many years.
While this technique is very strong, the ability of X-rays to detect atoms is determined by the number of electrons in a given atom. Since lithium ions only contain two electrons, X-rays have a hard time detecting the lithium ions in the battery materials. Neutrons, on the other hand, are not limited by the number of electrons in the atom, and can easily detect the lithium ions and other light ions that make up the battery material. They are thus very suitable for seeing the insides of a Li-ion battery and determining the structural features.
In this project, we will develop the experimental setup for neutron diffraction on Li-ion battery components as they charge and discharge. The ability to monitor the structure of the components when in use is extremely powerful, and we expect to gain new and valuable insight into the workings of a series of novel battery materials. The project is a collaboration between the University of Southern Denmark in Odense, Denmark, and the Heinz Maier-Leibnitz Zentrum (MLZ) research reactor outside Munich in Germany.