There is EMDrive and the various NASA Ion Drive projects. They all develop less than 1/10000 the thrust of chemical fuels. EMDrive uses no fuel and Ion Drives use about 1/10 the fuel of rockets (specific impulse is 10x). Useless for getting off the planet. But rockets only carry a couple of minutes of fuel. Scale exotic engines up to say 1/500th the thrust of rockets and it doesn't take long space before you are passing a rocket. Can ion thrusters be scaled up? NSTAR engines weigh 48 kg including the thruster, power processing units, xenon feed system, and control interface. Three of those and 475 kg of xenon will impart delta V of over 10 km/s to the Dawn probe, itself weighing about 600 kg without those thrusters. The Dawn engines have a specific impulse of 3100 s and thrust of 90mN (270 mH total). The Dawn spacecraft (the rest of it) weighed 600 Kg. 10 km/s is about 3 km/s over escape velocity. Just for comparison the Lunar Lander weighed 16000 Kg, 11,000 Kg was fuel and 500kg was rocket engines, tanks, etc. The descent stage produced 45.04 kN of thrust. The ascent stage produced 16 kN of thrust. The LEM engines had a specific impulse of about 311 seconds. So it is just a matter of improving the specific impulse and total engine output.