Unlike bake pads, these brushes are conductive. So their dust should react to magnetic fields, which are everywhere in these motors. I would expect the dust to settle or cake onto any number of other metal surfaces rather than drift through the air like brake pad dust.
Since we're speculating, the brushes could also be some harder material, with Carbon Nanotubes impregnated, or graphene infused and coated, etc.
Also, although I don't have the numbers for your issue about strong magnets pushing it away, I've found you need REALLY strong B Fields to do this. In other words, are we sure this is an effect that is at play here? (I'm asking)
No magnets doesn't mean no magnetic fields. I believe they were referring to permanent magnets. An electric motor without any magnetic fields would be a very odd device.
Ion drive thrusters. Not sure how one would translate them into a car, although there have been some on model aircraft, but they are a type of motor with a static magnetic field.
