cattletruck, you're right. It may be a race to see if effective electrical storage or a cure for cancer comes first.
Regarding an all-electric tail rotor, The current project involves the application of a torque-pitch coupling to a pair of small electrically driven main-rotors ~
Electrotor - SloMo. This feature should be applicable to a tail-rotor, also.
When the pilot increases the power to a rotor the torque reacts before the speed does. This increase in torque causes the collective pitch to automatically increase, then as the speed increases the torque and the collective pitch partially reduce.
Dave