It's a little scary seeing something that is commonly carried in our pockets engulfed in flames so quickly. While the lithium-ion batteries (also called Li-ion batteries) used in cell phones are unlikely to spontaneously combust, it's possible there will be an even safer option on the market soon.
While trying to find a material to prevent marine life from attaching to the bottom of ships, researchers stumbled upon a way to make non-flammable Li-ion batteries. The material, called PFPE, resembles the chemical structure of the electrolyte currently used in Li-ion batteries.
PFPE has been used for years as a lubricant for the gears of industrial machinery. While there is still testing to be done, the results look promising so far.