Chinese scientists claim solution to lithium phone batteries dying or catching fire

The accumulation of strands of lithium in liquid electrolytes – which shortens battery life – is preventable by converting liquids to solids, research finds

PUBLISHED : Tuesday, 09 October, 2018, 2:51pm
UPDATED : Tuesday, 09 October, 2018, 10:02pm

Chinese scientists have found a way to solve the common problem of lithium batteries for phones, tablets and laptops losing power quickly or even catching fire, according to a study.

The solution, published in the Science Advances journal on Friday, involves turning batteries’ liquid into a solid or quasi-solid, with the help of a chemical compound called LiPF6.

The resulting gel-like substance was found to be more stable than the conventional liquid, remaining inert for more than 400 hours of testing, compared with the traditional substance, the study said.

While lithium batteries have high energy density – energy carried by a battery relative to its weight – they are plagued by a common problem called dendrite, which can drain their power and even cause fire.

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“The uncontrolled lithium dendrite growth in liquid electrolytes still impedes lithium metal batteries from real commercialisation,” said Guo Yuguo, one of the lead authors on the study and a researcher with the Chinese Academy of Sciences in Beijing.

“Upgrading the traditional electrolyte system from liquid to solid and quasi-solid has therefore become a key issue for future lithium metal batteries.”

Dendrite are spikes and strands of lithium that grow on the battery’s anode – one side of the battery. When one charges a phone or an electric car, lithium ions move from one side to the other within the battery, travelling inside electrolyte, liquids or gels that can conduct electricity. After recharging a certain of number of times, enough dendrites accumulate to shorten battery life.

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“The scientific community considers the lithium dendrite formation one of the biggest hurdles of the lithium metal batteries for real applications,” said Wei Bingqing, a material scientist with the University of Delaware in the US who was not involved in the research. “This study reports a simple but practicable approach to tackle the dendrite problem.”

The chemical compound they use to trigger the liquid-to-gel process, LiPF6, is widely employed in commercial lithium-ion batteries, said Wei.

“This is a smart move in the sense of both lithium dendrite suppression and compatibility to the state-of-the-art technologies applied in the lithium-ion battery industry.”

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The problem could also cause phones to catch fire when charging. This may have caused the spontaneous ignition and explosion of a Samsung Galaxy Note 7 in late 2016, said Sina Ebnesajjad, a chemistry editor with scientific journal publisher Elsevier.

Scientists have been studying ways to improve the life expectancy and safety of lithium batteries for years. In September, a Pacific Northwest National Laboratory research team in the US developed a new electrolyte. Guo and his team at the Chinese Academy of Sciences have now also designed a special electrolyte that suppresses dendrite formation earlier this year.

Guo said the newly published study can be adapted to current battery system technologies, suggesting promise in its future application.