Scientists develop a lithium-ion battery that won't catch fire

Scientists have developed a flexible lithium-ion battery that can not only operate under extreme conditions - including cutting, submersion, and simulated ballistic impact - but also does not catch fire.

Current Li-ion batteries are susceptible to catastrophic fire and explosion incidents -- most of which arrive without any discernible warning - because they are built with flammable and combustible materials, according to researchers from Johns Hopkins Applied Physics Laboratory (APL) in the US.

They noted that some phones were banned from airlines as a result of this danger, and the US Navy's prohibition of e-cigarettes on ships and submarines is a direct response to the need to reduce the flammability of such devices. With these batteries emerging as the energy storage vehicle of choice for portable electronics, electric vehicles, and grid storage, these safety advancements mark a significant step forward in transforming the way Li-ion batteries are manufactured and used in electronic devices, the researchers said.

In the research published in the journal Chemical Communications, the team described a new class of "water-in-salt" and "water-in-bisalt" electrolytes - referred to as WiS and WiBS, respectively. These electrolytes, when incorporated in a polymer matrix, reduce water activity and elevate the battery's energy capabilities and life cycle while ridding it of the flammable, toxic, and highly reactive solvents present in current Li-ion batteries. It's a safe, powerful alternative, the researchers said. "Li-ion batteries are already a constant presence in our daily lives, from our phones to our cars, and continuing to improve their safety is paramount to further advancing energy storage technology," said Konstantinos Gerasopoulos, a senior research scientist and principal investigator at APL.

"Li-ion battery form factors have not changed much since their commercialisation in the early 1990s; we still use the same cylindrical or prismatic cell types. The liquid electrolyte and required hermetic packaging have a lot to do with that," Gerasopoulos said. "Our team's efforts have generally been focused on replacing the flammable liquid with a polymer that improves safety and form factor.

We are excited about where we are today," he said. Additionally, the damage tolerance initially demonstrated with the team's flexible battery in 2017 is further improved in this new approach to creating Li-ion batteries. "The first generation of flexible batteries were not as dimensionally stable as those we are making today," Gerasopoulos said.