I’ve often marveled at the many happy accidents that lead to great discovery. There’s something unexpectedly thrilling about the tangle of used Scotch tape that helped scientists discover graphene’s nano-scale capabilities. There’s quotidian brilliance in the sandwich-style layering of gold particles to produce high-efficiency solar cells. Fortuitous advancements such as these are also producing extraordinary developments in the energy storage space.
Whereas in life it often pays to be well-organized, in energy storage technologies—and magnesium cathode materials in particular—it seems disorganization may be the key to increased capacity. Researchers have recently observed that tiny magnesium chromium oxide particles that are haphazardly scattered, rather than arranged in a precise sequence, offer increased energy storage capacity in magnesium-based batteries.\
A study published in Nanoscale by researchers at UCL and University of Illinois outlines these findings as well as a new method for producing a cathode material that can reversibly store magnesium ions at high voltage.
Today’s lithium-ion batteries are notoriously limited by the low capacity of carbon anodes. But researchers believe that including magnesium in cathode materials could make the batteries of the future smaller and able to store far more energy—and disordering the particles may further enhance that capacity.
“Lithium-ion technology is reaching the boundary of its capability, so it’s important to look for other chemistries that will allow us to build batteries with a bigger storage capacity and a slimmer design,” the study’s co-lead author, Dr. Ian Johnson, told Phys.org. “Magnesium battery technology has been championed as a possible solution to provide longer-lasting phone and electric car batteries but getting a practical material to use as a cathode has been a challenge.”
UCL researchers produced a disordered magnesium chromium oxide material in a low-temperature reaction. Collaborators at the University of Illinois at Chicago then compared the material’s magnesium activity with a conventional, ordered magnesium chromium oxide material. The results were surprising in that the two types of crystals behaved very differently. The disordered particles displayed reversible magnesium extraction and insertion, a process not shown in larger, ordered crystal formations.
“This suggests the future of batteries might lie in disordered and unconventional structures, which is an exciting prospect and one we’ve not explored before as usually disorder gives rise to issues in battery materials,” explained UCL Chemistry Professor Jawwad Darr. “We see increasing the surface area and including disorder in the crystal structure offers novel avenues for important chemistry to take place compared to ordered crystals.”
What other applications can you imagine for this discovery? Do you think that magnesium battery technologies may offer a higher-capacity alternative to lithium-ion batteries?