Earlier this month, engineers at the Toyota Research Institute of North America (TRINA) announced they made a breakthrough in magnesium battery technology that could lead to smaller, longer-lasting rechargeable batteries for “everything from cars to cell phones.” Magnesium metal has long been theorized as a much safer and more energy-dense alternative to current lithium battery technology, but research on magnesium-based batteries has previously been limited by a lack of suitable electrolyte.
Lithium metal, in its natural state, is unstable and can ignite when exposed to air. To make lithium-ion batteries safer, the ions are taken from the lithium metal and embedded into graphite rods, which are then used in batteries. However, this reduces the amount of actual metal, which limits the amount of power a battery can store.
Magnesium, on the other hand, is a very stable metal with the potential to store much more energy. As such, it has been considered a potential replacement for lithium in rechargeable batteries for some time. The main challenge is forming an electrolyte – the liquid that allows current to flow from the anode to the cathode – that does not degrade the magnesium.
Toyota researchers were discussing this challenge when they were overheard by a colleague who was working on hydrogen storage materials and their application to fuel cell technology, Rana Mohtadi. Mohtadi, a Toyota principal scientist and chemical engineer, realized her hydrogen storage material might solve the longstanding problem. They formed a team and with further experimentation, proved her theory correct.
“We were able to take a material that was only used in hydrogen storage and we made it practical and very competitive for magnesium battery chemistry,” said Mohtadi. “It was exciting.”
“The results really speak to the strength in our group,” added Energy Storage Group Manager Paul Fanson. “We try to put people from diverse backgrounds and diverse technologies together and allow them to collaborate. This is a great example of that working very successfully.”
The team produced a paper on their non-corrosive, boron-based electrolyte system, published in the Angewandte Chemie International Edition. They hope that other researchers outside of Toyota can find use in the material and hasten the development of usable magnesium-based batteries, since it could take as long as 20 years before magnesium-based batteries go mainstream.
“We want to make this electrolyte a standard for magnesium batteries… and we want other researchers to develop it further so these batteries can see the light of day,” said the paper’s lead author, Oscar Tutusaus.
Toyota is among the 155 companies to join the Science-Based Targets initiative and aims to reduce the negative impact of manufacturing and driving vehicles as much as possible, as part of its Environmental Challenge 2050.