Can a battery still work when it’s on fire?

It’s no secret that lithium-ion batteries, the things that power pretty much every technological device that we use in our daily lives, can sometimes catch fire and explode. One of the main causes of this is liquid electrolyte, used to conduct ions between the electrodes in the battery. Many believe that using a solid-state electrolyte instead would make batteries far less flammable, and this is something that a research team at Stanford University has been hard at work trying to achieve.

In a paper published last month, they detailed their recent success with a prototype battery that, when lit on fire, didn’t explode and continued working normally. The key was in the solid-state electrolyte the team had devised. They made it out of a mixture of decabromodiphenyl ethane (DBDPE), a flame-retardant material, and polyimide, a mechanical enforcer with a high melting point so it is not likely to combust. However, this was where they hit a snag.

Polyimide can’t conduct ions, which has to happen for the battery to work. So they added more ingredients to their mixture: polyethylene oxide (PEO) and lithium bistrifluoromethanesulfonylimide (LiTFSI), (try saying that one three times fast). These are polymers, which means they create low resistance where the electrolyte and the electrode meet, allowing the ions to flow. None of the batteries using this new solid-state electrode exploded when lit on fire, and, in a bonus the team wasn’t expecting, they continued to function even as they burned.

Since its still only in the prototype stage, the goal now is to build upon and perfect the technology. “The challenge now is to make the battery charge faster, have a higher energy density, and to last longer,” said the team.