MRI is best known for providing images inside the body, now with a new sodium scanning technique developed at the University of Nottingham it has been used to give new insights into the inner workings of next generation high-performance rechargeable batteries.
Researchers at the Sir Peter Mansfield Imaging Centre developed a novel technique using high and ultra-high magnetic field scanners to use the body's natural sodium (salt) content to provide a more detailed picture of tissue health and disease.
This technique was adapted for use in a new study led by the University of Birmingham and in collaboration with the University of Nottingham to detect the movement and deposition of sodium metal ions within a sodium battery. This will enable faster evaluation of new battery materials, and help to accelerate this type of battery's route to market. The research has been published in Nature Communications.
It's quite unusual for clinical healthcare techniques to be translated for Chemistry and Physics experiments in this way, it usually happens the other way round. However, for this research it worked really well and we were able to translate our medical methodology in sodium MRI to the energy sector with great results. As in body scans the sodium in the batteries has the capacity to give us a much clearer and detailed picture of the structure, giving a clear image of the parts inside the batteries that are working well or not.
Sodium batteries are widely recognised as a promising candidate to replace lithium ion batteries, currently widely used in devices such as portable electronics and electric vehicles. Several of the materials required to produce lithium ion batteries are critical or strategic elements and, therefore, researchers are working to develop alternative and more sustainable technologies.
Although sodium appears to have many of the properties required to produce an efficient battery, there are challenges in optimising the performance. Key amongst these is understanding how the sodium behaves inside the battery as it goes through its charging and discharging cycle, enabling the points of failure and degradation mechanisms to be identified.
This imaging technique will enable scientists to understand how the sodium behaves as it interacts with different anode and cathode materials. They will also be able to monitor the growth of dendrites – branch-like structures that can grow inside the battery over time and cause it to fail, or even catch fire.
Dr Melanie Britton from the University of Birmingham's School of Chemistry led the research, she said: "Because the battery is a sealed cell, when it goes wrong it can be hard to see what the fault is. Taking the battery apart introduces internal changes that make it hard to see what the original flaw was or where it occurred. But using the MRI technique we've developed, we can actually see what's going on inside the battery while it is operational, giving us unprecedented insights into how the sodium behaves."
This technique gives us information into the change within the battery components during operation of a sodium ion battery, which are currently not available to us through other techniques. This will enable us to identify methods for detecting failure mechanisms as they happen, giving us insights into how to manufacture longer life and higher performing batteries.
The techniques used by the team were funded by the Birmingham-Nottingham Strategic Collaboration Fund. The development of novel materials and analytical characterisation is a primary focus of the Birmingham Centre for Energy Storage and Birmingham Centre for Critical Elements and Strategic Materials within the Birmingham Energy Institute. The research team also included scientists from the Energy materials group in the University of Birmingham's School of Metallurgy and Materials, and from Imperial College London.
