Ellen Phiddian
Cosmos science journalist
Korean researchers have found a way to grow crystals that they say could end up in lithium-ion batteries capable of powering an electric vehicle for 1 million kilometres.
The researchers have made a part of a battery – the cathode – that degrades much more slowly than typical cathodes.
If added to a rechargeable lithium-ion battery, it would last significantly longer, with more charging and discharging cycles.
“We have introduced a new synthesis strategy to enhance the durability of nickel-based cathode materials,” says senior author Professor Kyu-Young Park, a materials scientist at Pohang University of Science and Technology, South Korea.
Their cathode-growing method is described in a paper in ACS Materials & Interfaces.
Commercial lithium-ion batteries usually use tiny nickel-based crystals in their cathodes. These crystals can make the battery very energy-dense, but they degrade over time as they charge and discharge.
These researchers sought to fix this degradation by making a “single-crystal” nickel cathode, which is much more durable.
They found that at a critical temperature, 850°C, they could grow high-quality single crystals.
This heat made the grain size of the crystals larger, with no pores or spaces. This process is called “densification”, and densified crystals are much harder and more robust.
Cathodes made at this temperature retained their high capacities when the researchers tested them with charging and discharging.
“We will continue our research to make secondary [rechargeable] batteries for electric vehicles cheaper, faster, and longer-lasting,” says Park.
Batteries for electric vehicles are currently falling dramatically in price, with one major manufacturer saying it is slashing the costs of its batteries by 50%.
