One step closer to aluminium-ion batteries

Scientists from the US, Australia and South Korea have demonstrated a strategy for designing active materials for rechargeable aluminium-ion batteries that could be used in future for renewable energy storage.

While lithium-ion batteries have enjoyed remarkable success powering mobile electronic devices, in renewable energy applications they are fraught by limited cycle life, safety concerns and relatively high costs. Aluminium-ion batteries have thus been seen as ideal contenders for this space, given aluminium is the third most abundant element in the Earth’s crust behind oxygen and silicon. It also has the one of the highest theoretical volumetric capacities on account of its multiple redox states.

“Developing batteries using aluminium has received a lot of expectation for delivering high energy to price ratios,” said Dr Dong Jun Kim, formerly of Northwestern University and now based at UNSW. But up until now, finding appropriate host electrodes for insertion of complex aluminium ions had been a fundamental challenge.

“We found a novel way to design rechargeable aluminium batteries by employing a redox-active macrocyclic compound as the active material,” Dr Kim said. In other words, he and his team managed to use a large organic chemical compound as the part of the battery that stores energy, something that previously had researchers stumped.

“We believe the research discussed in the article opens up a new approach to designing aluminium-ion batteries that could be of interest to scientists investigating next-generation electrochemical energy storage,” Dr Kim said.

Dr Kim said the results of the study, published in the journal Nature Energy, showed “promising battery performances”; however, he stressed that it is early days and improvement will be required in every aspect of the technology. He will therefore continue to research aluminium-ion batteries while examining the potential of using other elements.

“I look forward to further research on utilising redox-active organic molecules for multivalent-ion intercalation batteries such as aluminium, magnesium, zinc and calcium,” Dr Kim said.

Image credit: ©stock.adobe.com/au/Björn Wylezich

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