At breakthrough for developing the batteries of the future was announced this week by researchers at Cambridge University, Stony Brook University, and New York University. The research group has developed a methodology based on magnetic resonance imaging, the MRI we are familiar with, to look inside a battery without destroying it.
Advanced batteries are the major barrier to electrification of a significant share of transport and for better, lighter and cheaper electronics.
The research group’s technique is described in the journal Nature Materials. As well as a look inside without destruction the technique may also improve battery performance and safety by offering diagnostics of battery internal operations. Therein lies the breakthrough.
The MRI has been extremely successful in the medical field for visualizing disorders and assessing the body’s response to therapy. But an MRI isn’t usually used in the presence of a lot of metal, a primary component in many batteries’ shells, as part of the anode and cathode and in many cases the electrolyte. The problem is metallic surfaces and dense concentrations conduct electricity that effectively block the radio frequency fields that are used in a MRI to see beneath surfaces or inside the human body. With the radio waves shielded or absorbed and converted to electrical current – there isn’t anything to see.
The research group has cleverly turned this limitation into a virtue. Because radio frequency fields do not penetrate metals, one can actually perform very sensitive measurements on the surfaces of the conductors. Using 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. Those deposits can also detach from the electrode surface, eventually leading to overheating, battery failure, and, in some cases – to a fire or an explosion.
This breakthrough is sure to speed development up because the ability to visualize small changes on the surface of the batteries’ electrodes, which would allow in principle, for testing of many different battery designs and materials while operating under normal conditions.
The breakthrough comes from a collaboration between Clare Grey, associate director of the Northeastern Center for Chemical Energy Storage and a professor at Cambridge and Stony Brook universities, and Alexej Jerschow, a professor in the Department of Chemistry at New York University who heads a multi-disciplinary MRI research laboratory. The group isn’t saying whose brainstorm found the virtue in the limitation, but that’s OK.
Jerschow illustrates the import by explaining, “New electrode and electrolyte materials are constantly being developed, and this non-invasive MRI technology could provide insights into the microscopic processes inside batteries, which hold the key to eventually making batteries lighter, safer, and more versatile. Both electrolyte and electrode surfaces can be visualized with this technique, thus providing a comprehensive picture of the batteries’ performance-limiting processes.”
Grey points out why the technique offers such an advantage, “MRI is exciting because we are able to identify where the chemical species inside the battery are located without having to take the battery apart, a procedure which to some degree defeats the purpose. The work clearly shows how we can use the method to identify where lithium deposits form on metal electrodes.” Grey adds, “The resolution is not yet where we want it to be and we would like to extend the method to much larger batteries, but the information that we were able to get from these measurements is unprecedented.”
It’s a start that works. Other team members include S. Chandrashekar, a postdoctoral fellow at both Stony Brook and New York Universities; Nicole Trease, a postdoctoral fellow at Stony Brook University; and Hee Jung Chang, a Stony Brook University graduate student.
Looking ahead the group offers that the method could lead to the study of irregularities and cracks on conducting surfaces in the materials sciences field. In addition, they add, the methods developed here could be highly valuable in the quest for enhanced battery performance and in the evaluation of other electrochemical devices, such as fuel cells.
They might want to consider more thoroughly the impact the technique might have on catalysts – but that field will surely find them quite soon.
Chandrashekar sums up briefly, “We still have some way to go to make the images resolve better and make imaging time shorter. However, we feel that with this work, we have made the field wide open for interesting applications.”
Battery development has been racing ahead for a decade when many used to believe little progress could be made. Now we have a technology that puts the activity inside a battery in view. Should Chandrashekar’s prognosis come to pass soon and at high resolution and high speed “shutter speed” so to speak, development for batteries should gather much more momentum and achieve results faster and at lower cost.
But that’s just one field. The fuel cell field and other catalyst processes can use a boost of high-speed development diagnostics, too.
This is great news. Congratulations are in order. We’d sure like to know though, who was the person or who were the folks who had the brainstorm? That would be a double up on the congratulations.