Researchers at the University of Birmingham in the UK are using magnetic resonance imaging (MRI) systems to test the performance of the latest sodium battery designs.
The technique, which was developed to detect the movement and deposition of sodium metal ions within a sodium battery, will enable faster evaluation of new battery materials, and help to accelerate how new versions of the battery technology are commercialised. Manufacturers such as Faradion are already shipping sodium battery systems for transport and stationary energy storage systems (ESS).
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.
A team, led by Dr Melanie Britton in the University of Birmingham’s School of Chemistry, has developed a technique, with researchers from Nottingham University, that uses MRI scanning to monitor how the sodium performs during operation
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. The 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. These are more common in lithium ion battery cells and a major cause of failure and MRI techniques are already used to examine lithium ion cells on the production line.
“Because the battery is a sealed cell, when it goes wrong it can be hard to see what the fault is,” said Britton. “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 provides 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,” she added. “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 first designed in a collaboration with researchers at the Sir Peter Mansfield Imaging Centre at University of Nottingham which was funded by the Birmingham-Nottingham Strategic Collaboration Fund. This project, with access to MRI technologies from Phlips and GE, is developing MRI scanning of sodium isotopes as a medical imaging technique and the team were able to adapt these protocols for use in battery imaging.