The Boeing 787 had problems with the aircraft's own lithium batteries going into thermal runaway and catching fire.[1] Fortunately, on the ground at an airport. When it happened a second time, all 787s were grounded for months.

I suspect that once there's a better battery technology, maybe lighter lithium-iron-phosphate or a noncombustible solid battery, the current lithium ion technology will be prohibited on aircraft.

[1] https://edition.cnn.com/travel/article/boeing-787-dreamliner...