Seems very unlikely, Stirling engines are famously inefficient, and there are no links in the story to further detail.

As is all-too-common, the language is loaded with errors. Some may be misguided attempts to explain via analogy. In the end, they´re just errors. In explaining science, accuracy isn´t an option.

The mention of "battery" is a flat error. A battery produces a current directly from a chemical reaction. This design operates

OK -- the system described is intended to produce the power needed to run on-board electronics and the transmitter[s]. The image [and language] seems to suggest this device provides propulsion power. Not so.

The article does discuss the use of this reactor in an ion-drive system.

So -- this design uses the heat of radioactive decay to heat the gas [working fluid] of the Stirling engines, which mechanically drive generators to make the electricity to power the on-board electronics.

#2: Indeed, much is left unaddressed. Perhaps the range of temperature in the hard vacuum of space makes these Stirlings more efficient? One must wonder whether the direct heat-to-electricity solid-state devices have really poor efficiency, or really poor reliability?

Duh...dilithium crystals.

The efficiency can be increased by adding a cast iron fan driven by the Stirling engine to blow bypass ions around the Nuclear engine...

Thorium is the future.
Proven working reactor.
We have enough fuel for 800 years using today consumption as a baseline.

Fairy dust and good intentions.

The future is LENR (aka cold fusion). Hot e-Cat devices that can generate 1MW of heat in device of volume of one half cubic meter (1.2m diameter x 0.4m length) are on the market, if you have a megabuck or two. Input power to create 1MW of heat is around 100kW. Combine this with a smaller device, where the smaller feeds the larger, and you get the kind of power needed to push a spacecraft around (with, say, a Vasimir engine).