Any impulse / reaction engine is subject to the Tsiolkovsky rocket equation. It's just that with higher specific impulse and reactant velocity the total mass is reduced.
Since the rocket equation is a function of the effective velocity times the natural log of the wet/dry mass ratio, changes in exhaust velocity matter more than changes in propellant mass: you're better off with heavier propellant moving faster, than lighter propellant moving slower.
Ion drive engines tend to use xenon (a heavy nobel gas) for this reason. Unfortunately, xenon is rare even on Earth, and extraordinarily rare in space -- tanking up on a road trip would be difficult.
Since the rocket equation is a function of the effective velocity times the natural log of the wet/dry mass ratio, changes in exhaust velocity matter more than changes in propellant mass: you're better off with heavier propellant moving faster, than lighter propellant moving slower.
Ion drive engines tend to use xenon (a heavy nobel gas) for this reason. Unfortunately, xenon is rare even on Earth, and extraordinarily rare in space -- tanking up on a road trip would be difficult.