Scientists develop non-explosive lithium-ion batteries

The thin polyethylene film that prevents a lithium-ion battery from overheating. Image courtesy of Stanford University.

A team of scientists have announced a new lithium-ion battery design which they believe is much less likely to explode.

The new battery, developed by researchers at Stanford University in the US, hopes to overcome one of the major shortcomings of these devices.

Common lithium-ion batteries, due to their chemistry, are liable to violently explode when subjected to overheating, overcharging or physical punctures.

Critically, unlikely traditional designs, the new architecture will automatically shut down when overheating, and will only restart when sufficiently cool.

“People have tried different strategies to solve the problem of accidental fires in lithium-ion batteries,” said Zhenan Bao, a professor of chemical engineering at Stanford.

“We’ve designed the first battery that can be shut down and revived over repeated heating and cooling cycles without compromising performance.”

In order to add this functionality to the new batteries, the Stanford team made use of a new nanotechnology-based approach.

One of the electrodes of the battery was coated in a thin film of polyethylene plastic, which itself was embedded with small shards of graphene-coated nickel. These so called ‘nanospikes’ would only conduct electricity when the battery was within a certain range.

Should the battery become too hot, thermal expansion would spread apart the conductive nanospikes blocking the discharge of current.

The specific battery created by the researchers would shut down once the polyethylene film had reached around 70 degrees, however their technology can theoretically be adapted to produce batteries which shut themselves down at a range of different temperatures.

They believe that due to the simplicity and adaptability of their design, it has great commercial promise.

“Compared with previous approaches, our design provides a reliable, fast, reversible strategy that can achieve both high battery performance and improved safety,” said Yi Cui, another Stanford engineer involved in the project. “This strategy holds great promise for practical battery applications.”

In the future these batteries could go some way to reducing the number of fires and injuries caused by exploding batteries, something which has recently caught media attention due to the large number of exploding ‘hoverboards’.

As well, less volatile lithium-ion batteries could also be used in space, where they are currently frowned upon due to their inherent volatility.