Korean researchers has developed an innovative new electric vehicle (EV) battery technology, which is more energy efficient than a gasoline engine or existing lithium-ion batteries.
The new technology enables drivers to replace the battery instead of charging it, saving the charging time for them. It is lighter than existing EV batteries while retaining more energy power with reduced risk of explosion.
The new battery was developed by researchers of the Ulsan Institute of Science and Technology (UNIST) led by Professor Cho Jae-pil of the Energy and Chemical Engineering Department.
The “aluminum-air flow battery” is more energy efficient than lithium-ion batteries while it does not explode.
The new battery is not a rechargeable secondary battery, but a one-time-use primary battery. When applied to an electric car, electricity can be supplied by just replacing aluminum metal. According to the researchers, aluminum has superior energy density compared to the same weight of gasoline.
"While 1kg of gasoline represents 1,700 Wh of energy density in a car, that of aluminum applied to an aluminum-air flow battery is 2,500 Wh per kg," said Cho, adding, “With the energy density like this, we can make a battery that enables an electric car to go up to 700 km with one-time replacement."
The technology is a “metal-air battery” type that gets electrical power through the reaction of various metals (fuels) with air. Metal-air batteries have been receiving attention as a next-generation battery because they are more energy-dense than lithium-ion batteries. In particular, big expectations have been drawn to aluminum because it is light in weight and cheap, and does not explode. Its theoretical capacity is bigger than lithium, too.
However, the existing aluminum-air batteris are easily discharged due to the accumulation of aluminum by-products during the battery operation. Professor Cho’s team solved this problem by developing an “electrolyte flow” method. When they applied the pump to the battery and let the electrolyte flow, the byproducts did not accumulate, and the performance was maintained.
A high-performance catalyst (silver-manganese oxide nanoplate catalyst) that activates the reaction at the air-receiving electrode has also been newly developed. The catalyst-applied aluminum-air flow battery is expected to increase the travel distance of the electric car because its energy density is high and it does not explode.
The first author of the paper Ryu Jae-chan, a Ph.D. student at UNIST Department of Energy Engineering, said, "We solved the problem of precipitation of aluminum electrodes by developing the electrolyte flow technology and achieved high energy density by applying high-performance catalysts to air electrodes,” adding, “We also clarified the principle of stable and yet high activity of the new catalyst by using an atomic level-transmission electron microscope. "
The discharge capacity of aluminum-airflow battery increased 17-fold compared to the conventional aluminum air battery. The capacity of newly developed silver-manganese oxide-based catalysts was comparable to that of the conventional platinum catalysts (Pt / C). As silver is 50 times less expensive than platinum, it is also competitive in terms of the price.
The study was published in the top global journal Nature Communications on September 13.