Cheap materials excite researchers with super-fast charging power

27 Jul 2018

Image: Bacho/Shutterstock

Lithium-ion battery charging is getting faster by the year, but the discovery of a new bunch of cheap materials could make this look like child’s play.

If electric vehicles (EVs) are to truly to become mainstream, they will need to equal or better the speed at which a fossil fuel-powered vehicle can be refuelled.

Right now, despite the advent of faster charging methods over the years, it would take the average EV consumer 20 minutes to charge a battery to 80pc, with nearly double that amount of time for a full charge.

Now, a recent discovery by a team of researchers from the University of Cambridge could help pave the way for significantly faster lithium-ion battery recharging that would not only benefit EVs, but most consumer electronics.

In a paper published to Nature, the team said it has identified a group of cheap but complex materials known as niobium tungsten oxides, capable of supercharging batteries.

While these materials won’t lead to higher energy densities and long-duration batteries, their complex crystalline structure allows for lithium ions to move through them at blistering speeds, equating to super-fast charging.

On top of that, their physical structure and chemical behaviour give researchers a valuable insight into how a safe, rapid-charging battery could be constructed.

This particular route of research taken has differed from many of the team’s peers as others have typically tried to make charged particles smaller.

Taking a different route

“The idea is that if you make the distance the lithium ions have to travel shorter, it should give you higher-rate performance,” said Dr Kent Griffith, first author of the paper.

“But it’s difficult to make a practical battery with nanoparticles; you get a lot more unwanted chemical reactions with the electrolyte, so the battery doesn’t last as long, plus it’s expensive to make.”

As for why these ‘magic’ materials haven’t received much attention, Griffith said it is likely due to their complex atomic arrangements. However, he suggested that the structural complexity and mixed-metal composition are the very reasons the materials exhibit unique transport properties.

Looking to the future, tech companies and battery producers are likely to be very interested in the technology as the materials are cheap and simple to produce.

“A lot of the nanoparticle structures take multiple steps to synthesise and you only end up with a tiny amount of material, so scalability is a real issue,” Griffith said.

“But these oxides are so easy to make and don’t require additional chemicals or solvents.”

Colm Gorey was a senior journalist with Silicon Republic