The word "breakthrough" is always a flag to me. It's either a discovery of some potential that hasn't been fully researched yet and once it is it's found to not be as practical or cost effective, or it's in development but something will happen that stalls or blocks it from getting into production (whether that be engineering, science, or intentional shelving for other reasons).
What I look for is some stats that are much better than existing,tested on existing prototypes with good results, and announced for the model due out the next year with an actual price tag.