Muons are an excellent probe of internal magnetic fields; they can be used to investigate magnetic order in materials known or expected to be antiferromagnetic and they can also help us to understand diffusion in metals. Muons have recently been used to measure the microscopic diffusion process in lithium battery materials. Li-ion batteries have global use in smartphones, home appliances, electric vehicles and airplanes. The ionic diffusion rate in a lithium battery determines how quickly it can be charged and discharged and can be quite hard to measure. The muon, however, is sensitive to magnetic fields, so we can use it to probe magnetism. So if you’ve got a lithium atom diffusing past then you can see that the magnetism from the nuclear moments will change as its going past. As it starts to speed up it will narrow the signal so you get a smaller signal.

"One of the most important scientific problems to solve in our society is how to convert and store clean energy. In order to accomplish a paradigm shift in this field, we need to understand the fundamental dynamical processes that govern the transfer of energy on an atomic scale. Although Li-ion batteries are one of the great achievements of modern materials electrochemistry, we are currently reaching the limits in performance using the available electrode and electrolyte materials. In order to build better batteries, a breakthrough in science and technology is needed. Only recently, technical developments at especially large-scale experimental facilities such as ISIS, have opened new possibilities for studying such material’s properties in a straightforward manner.​​" - ​Jun Sugiyama, Toyota Central Research & Development Laboratories, Japan and Dr. Martin Månsson, EPF Lausanne, Switzerland