Aerogel is the world’s best insulator. It is an extremely low density synthetic solid. The liquid is extracted from a silica dioxide gel and replaced with up to 99.8% air (by volume), which is trapped within the tiny pores of the structure, making heat transfer incredibly limited.
As well as being an incredible insulator, aerogel can also support up to 4,000 times its own weight, and can withstand a direct blast from 2 pounds of dynamite.