Eventually we will get solid state batteries working. Those do not combust no matter what you do to them (short of, like, throwing them in a smelter). They also have many other advantages: much greater density, unlimited lifetime (because of no electrolyte eating away at the poles), ability to use them as structural components, faster charging...

There are such batteries in the works, but the problem they have a lot of catch-up to do. Even if they're 50% better, than current lithium, lithium keeps getting better every year, so it's a moving target... when solid state hits the market in 5 years, it's advantage may be gone, until it also benefits from years of improvement.

Hopefully, eventually lithium tech will hit a plateau, and then it will make sense to switch to pouring all our resources into solid state.

There are also partially solid (gel-like) electrolytes already in use, that are significantly less flammable than liquid.

On the other end of the spectrum, there's research into sodium batteries. These store a lot more energy than lithium, but also make a lot bigger boom. Like the difference between a car fire that's difficult to extinguish and, well, a 2000lb bomb... But for applications where performance is the only thing that matters, they sound pretty cool.