Scientists closer to producing safer and longer-lasting lithium battery

Researchers from Arizona State University have developed a new method to produce lithium-metal batteries that allows for a controlled dendrite growth, which makes them safer and longer-lasting.

The team found that using a 3-D layer of polydimethylsiloxane (PDMS), or silicone, as the substrate of the lithium metal anode can mitigate the formation of dendrites, which are needle-like growths that appear on the lithium surface.

The finding is relevant for both lithium-ion and lithium-air batteries, as well as for other metal-anode-based batteries, the team says.

Those formations induce unwanted side reactions that reduce energy density, and at worst, cause shorting of the electrodes that can lead to fires or explosions.

The implications of involving a three-dimensional layer o silicone, the scientists say, are relevant for both lithium-ion and lithium-air batteries, as well as for other metal-anode-based batteries.

"Almost all metals used as battery anodes tend to develop dendrites," says University's professor of School for Engineering of Matter, Transport and Energy, and lead on the research paper, Hanqing Jiang. "For example, these findings have implications for zinc, sodium and aluminum batteries as well."

In the paper published in the journal Nature Energy, Jiang notes the team didn't approach the problem from a materials or electrochemical perspective, but instead looked for solutions as mechanical engineers.
"We already know that tiny tin needles or whiskers can protrude out of tin surfaces under stress, so by analogy we looked at the possibility of stress as a factor in lithium dendrite growth."

The researchers say potential applications of their finding range from personal electronic devices to powering electric cars for exceptionally longer periods to being the back-up electric supply for solar power grids.

Lithium prices have more than doubled over the past two years, to trade at around $13,375 a tonne this week. But according to some, such as Morgan Stanley, they will peak this year and then fall to $7,332 a tonne by 2021. Citi also sees a fall in the long-term price to $7,500 a tonne due to a potential oversupply.