We’re finally close to making an eco-friendly battery that lasts for days

26 Mar 2018

Image: Bloomicon/Shutterstock

We could soon be done with unsustainable lithium-ion batteries, in favour of longer-lasting ones for any battery-powered device.

The world has become reliant on lithium-ion batteries because of their use in all our gadgets, from mobile phones to tablets, and also the electric vehicles that aim to replace polluting, fossil fuel-powered cars.

The only problem is that these batteries are not sustainable, being sourced – many times unethically – from vast mines, and becoming harmful when dumped.

But now, a research team from the University of Texas at Dallas has revealed a new design that promises not only to be more environmentally friendly, but to last considerably longer than existing ones.

The team detailed its findings in the journal Nature Nanotechnology, revealing its high-powered, environmentally safe lithium-sulphur substitute.

Lithium-sulphur batteries are less expensive to make, weigh less and store almost twice the energy of lithium-ion batteries, and are better for the environment.

Dr Kyeongjae Cho of the research team said that, on average, they have a capacity up to five times higher than lithium-ion equivalents.

However, the major downside is that sulphur is a poor electrical conductor, thereby becoming unstable over just a few charge-and-recharge cycles, as well as the fact that electrodes break down during the charging process.

To get around the problem, scientists have tried to improve them by putting lithium metal on one electrode and sulphur on the other, but this has shown no success so far as the metal is often unstable while the sulphur is too insulating.

‘This was what everyone was looking for’

That was until the Dallas team discovered that molybdenum – a metallic element often used to strengthen and harden steel – creates a material that adjusts the thickness of the coating when combined with two atoms of sulphur.

Thinner than the silk of a spider web, the material improved stability and compensated for poor conductivity of sulphur, thus allowing for greater power density and making lithium-sulphur batteries more commercially viable.

“This was what everyone was looking for, for a long time,” Cho said. “That’s the breakthrough. We are trying to suppress side reactions. It’s a protection technology.

“We are taking this to the next step and will fully stabilise the material and bring it to actual, practical, commercial technology.”

Colm Gorey was a senior journalist with Silicon Republic