Long story short, there really isn't a good way to make a flipper as fast and powerfull as a co2 one with electric motors.
You can either gear it to get the same strength with less speed or to get the same speed but not a whole lot of strength.

Using bigger motors might do the trick but you'll be overweight in no time.

Perhaps someone knows about a brushless one that has the specs to come close to the speed/power ratio your looking for.