I read an article in NEW SCIENTIST magazine lately,
and pardon me if the info was erroneous, or I misunderstood
something, but it mentioned something astonishing

A material [it said] called graphene, if made into a layer of carbon
one atom thick, has electrons moving around in the material rather slowly
at room temperature.
It didn't mention any velocity values.
But cool down the graphene to near absolute Zero and the electrons
will wizz around inside the material at relativistic speeds;
so claimed the article.

That doesn't make sense.
How could electrons pick up energy and move faster when things get colder inside a substance?