Small graphene powerbanks are already available on Amazon at reasonable prices.
Many appear to be designed for drone usage where very rapid recharging is desirable.
Have my eye on a 9000mAh unit at about $50.
Dang...and I "try" to stay abreast of technology. I had no idea that the practical applications were THAT far advanced.
Graphene certainly appears to be a wonder material with huge potentialities in many, many fields. I wonder what we will find we can do once manufacturing in micro-G becomes possible. Room-temperature superconductivity??
Maybe graphene is another name for "dilithium".