I have used supposed Graphene LiPo batteries in model aircraft, specifically multi-rotor or "drone" to use modern day parlance. They tend to be very high C rated, starting at 70C and going upward depending on various types.
My experience, and that of others, is that these provide a very "punchy" output on demand without getting all stressy and puffing up. But they also have one characteristic that I personally find quite irritating ... when they give up the GIVE UP .... fast! Literally dropping off the edge of a cliff. Power output goes from Hero to Zero (sic) in a matter of moments, little tapering off.
Given how powerful the existing batteries are in the Zero range of motorcycles I question whether Graphene will do anything much for our benefit. We don't need more C of power output. We need greater energy density and the Graphene LiPo of today, at least, do not do anything to improve energy density for a given physical size.
In short - more free-flowing electrons but no improvement in pack energy density.