A wonder material that’s so far not been synthesized in quantities sufficient for economical practical applications. In short it costs too much for what you get.
Here’s the ultimate gamechanger:
A susbtance which would enable you to make a 35,000 km long cable of itself. If you do that, you have a space elevator. Transportation to orbit becomes extraordinarily inexpensive.
I figure 35,000 km = 35 million m^3 of a material 1 m wide, or 35 m^3 of a material 1 mm wide. 1 mm cable of Steel supposedly can bear 84 kg, at least at standard temperatures. (Squared off, 107 kg).
Since 1 m^3 of steel weighs 7580 kg, and we need 35 m^3, that’s a total weight of 274,750 kg, or 2,560 times more weight than the steel cable can hold.
If graphene is 1,000 times stronger per unit of weight than steel, we still need something about 3 times stronger...
Is graphyne 3 times stronger?