Ellen Phiddian
Cosmos science journalist
Chemical engineers have figured out a way to more than double the lifespan of high-voltage lithium-ion batteries.
The international team of researchers, based at the University of Queensland, has developed a lithium-ion battery which has a higher energy density than conventional batteries, uses less precious metal, and can stay stable for over 1000 cycles.
They’ve published their technique in Nature Communications.
“Our process will increase the lifespan of batteries in many things, from smart phones and laptops to power tools and electric vehicles,” says senior author and UQ researcher Professor Lianzhou Wang.
The team’s discovery revolves around the cathode of the battery: the positive side, which attracts negatively charged electrons as they move through a circuit.
At the moment, for commercial lithium-ion batteries to work they need the costly and hazardous metal cobalt in their cathodes – otherwise the cathodes corrode too easily. Cathodes without cobalt can make higher-voltage and thus more energy dense batteries, but the corrosion problem means their lifespan and function is limited.
Researchers are keen to find a coating that can protect the metals in the cathode without disrupting the battery’s performance.
Wang and colleagues discovered that an extremely thin epitaxial layer could protect a cathode made from lithium, nickel, and manganese. Epitaxy is a type of crystal growth in which the crystal’s atoms are aligned with the atoms in the substrate (the thing they’re growing on).
In this case, the researchers found that a specific material (made from lanthanum, nickel, manganese and oxygen) grown epitaxially on cathode particles could stop the cathode from dissolving.
The layer of crystal is only an atom thick – so it doesn’t require much material to have a big effect.
“This new approach features a minimal protective coating at a scalable process, paving the way for the deployment of these abundant high-voltage materials for next generation, high-energy batteries,” says Wang.
Wang says that other than being better performing and cobalt free, the battery operates very similarly to conventional lithium-ion batteries.
“The battery can be operated at higher voltage – about 4.5V, versus 3.7V for a normal lithium-ion battery – which means higher energy density can be delivered,” he points out.
The researchers are now planning to commercialise the technology.
“We are now in discussion with our industry partners to assess the scale-up production process and to evaluate the battery performance under various conditions,” says Wang.
He predicts that the battery could be ready for the market in two or three years.