Magnetic resonance imaging shows batteries' inner workings

The technique, described in Nature Materials and developed by researchers at Cambridge University, Stony Brook University and New York University, also creates the possibility of improving battery performance and safety by serving as a diagnostic of its internal workings.

According to a statement, MRI has been successful in the medical field for visualising disorders and assessing the body’s response to therapy. However, MRI is not typically used in the presence of a lot of metal — a primary component in many batteries. This is because conducting surfaces block the radio-frequency fields that are used in MRI to see beneath surfaces or inside the human body.

The researchers are said to have turned this limitation into a virtue. Because radio-frequency fields do not penetrate metals, it is possible to perform very sensitive measurements on the surfaces of the conductors. In the case of lithium-ion batteries, for example, the team was able to directly visualise the build-up of lithium metal deposits on the electrodes after charging the battery. Such deposits can also detach from the surface, eventually leading to overheating, battery failure, and — in some cases — to fire or explosion.