New technique could eliminate lithium battery fires

Lithium-ion batteries have always suffered from one teeny little problem – a tendency to burst into flames.

But scientists at Cambridge University have developed a simple, accurate way of monitoring what’s going on inside, and reckon they may be able to prevent this.

Over several charge and discharge cycles – particularly if the batteries are charged quickly – minute fibres of lithium known as dendrites can form on the carbon anodes. These can cause short circuits, causing the battery to overheat and catch fire.

It’s bad enough if this happens to a laptop – but lithium-ion batteries are also being used in electric cars.

“These dead lithium fibres have been a significant impediment to the commercialisation of new generations of higher capacity batteries that use lithium metal as the anode instead of the carbons used today,” says Professor Clare Grey.

Scientists have use theoretical models, along with optical and scanning electron microscopes, to study dendrite formation. But it’s never been possible to quantify accurately the amount of dendrites formed.

But in a Nature Materials paper, Grey describes using a new method based on Nuclear Magnetic Resonance (NMR) spectroscopy.

Exploding Batteries

“Fire safety is a major problem that must be solved before we can get to the next generation of lithium-ion batteries and before we can safely use these batteries in a wider range of transportation applications. Now that we can monitor dendrite formation inside intact batteries, we can identify when they are formed and under what conditions,” she says.

“Our new method should allow researchers to identify which conditions lead to dendrite formation and to rapidly screen potential fixes to prevent the problem.”