Ramjets are more efficient than turbojets supersonically, not worth bothering with subsonically, and don't work at all under a couple hundred miles per hour.
A "motorjet" is a turbojet with no turbine, that utilizes an external source to drive the compressor.
The Idea is for a ramjet, which spike
houses an electric motor that drives retractable fan blades. (the parts of the idea which are original are "electric motor" & "retractable")
At low speed the fan is run, blades extended, properly feeding the (motor)jet. When the desired speed is reached, the motor is turned off, the blades retracted, and operation as a full ramjet, with no moving parts, commences.
(At an opportune time during the ramjet phase the blades can be partially re-extended to recharge the batteries.)
Note: There's the possibility of using the engine as an electrically-driven "plain old" ducted fan as well, without a running jet, if the internal contour of the ramjet allows for it.
[search-engine skimmers: this isn't the same principle as the J58 found on the SR-71: that's a turbojet which has a variable bypass after the compressor to the afterburner]