The new technology enables drivers to have their battery packs replaced instead of charging them, which the researchers believe will troubleshoot the slow charging problem associated with existing EV battery technology. It is also said to provide lightweight, high-energy density power sources with little risk of catching fire or explosion.
When compared to the existing lithium-ion batteries (LIBs), the new type of aluminium-air flow battery is said to outperform the others in terms of higher energy density, lower cost, longer cycle life, and higher safety.
Aluminium-air batteries are primary cells, which means they cannot be recharged via conventional means. When applied to EVs, it will produce electricity by simply replacing the aluminium plate and electrolyte. Considering the actual energy density of gasoline and aluminium of the same weight, aluminium is superior, the researchers say.
"Gasoline has an energy density of 1,700 Wh/kg, while an aluminium-air flow battery exhibits a much higher energy densities of 2,500 Wh/kg with its replaceable electrolyte and aluminium," says Professor Jaephil Cho of UNIST. "This means, with 1kg of aluminium, we can build a battery that enables an electric car to run up to 700km."
The new battery works much like metal-air batteries, as it produces electricity from the reaction of oxygen in the air with aluminium. Metal-air batteries, especially aluminium-air batteries, have attracted attention as the next-generation battery due to their energy density, which is higher than that of LIBs. Indeed, batteries that use aluminium, a lightweight metal, are lighter, cheaper, and have a greater capacity than a traditional LIB, according the UNIST.
While aluminium-air batteries are one of the highest energy densities of all batteries, they are not widely used because of problems with high anode cost and by-product removal when using traditional electrolytes. Professor Cho believes to have solved this issue by developing a flow-based aluminium-air battery to alleviate the side reactions in the cell, where the electrolytes can be continuously circulated.
In the study, the research team has prepared a silver nanoparticle seed-mediated silver manganate nanoplate architecture for the oxygen reduction reaction (ORR). They discovered that the silver atom can migrate into the available crystal lattice and rearrange manganese oxide structure, thus creating abundant surface dislocations.
Thanks to improved logevity and energy density, the team anticipates that their aluminium-air flow battery system could potentially help bring more EVs on the road with greater range and substantially less weight with zero risk of explosion.
"This innovative strategy prevented the precipitation of solid by-product in the cell and dissolution of a precious metal in air electrode," says Jaechan Ryu, first author of the study. "We believe that our AAFB system has the potential for a cost-effective and safe next-generation energy conversion system."
