Using MRI machines, researchers at Cambridge University, Stony Brook University and New York University have developed methodology to analyze internal battery structure after a battery failure. Because radio frequency fields do not penetrate metals, the scientists were able to use the MRI machine to perform very sensitive measurements on the surfaces of the conductors. In the case of the popular lithium-ion batteries, for example, the team was able to directly visualize 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. Scientists comment this method could be highly valuable in the quest for enhanced battery performance and in the evaluation of other electrochemical devices, such as fuel cells.