Mats Lewan has published a blog post today on his An Impossible Invention website where he proposes a way by which the E-Cat could possibly work. He gives much credit to insights provided by Bob Greenyer, and also information found in the patent documents of Francesco Piantelli.
The full post is here (Mats says it will be expanded upon over time): https://animpossibleinvention.com/2016/03/07/finally-this-is-possibly-how-the-e-cat-works/
Here’s a very simplified summary of the steps that Mats thinks are possibly involved. Please refer to his post for details.
1. Expose a transition metal like nickel to hydrogen.
2. Obtain hydrogen atoms with one extra electron (i.e. Hydrogen ions).
3. Trigger the system somehow: e.g. thermal shock, mechanical shock, electric or magnetic pulse.
4. Triggering will lead to an electron in the nickel atoms being replaced by the H- ion.
5. The H- ion with a much larger mass than an electron orbits closer to the nucleus of the nickel atom than the electron, and sends out Auger electrons and X-rays.
6. Low energy X-ray photons are absorbed by shielding such as lead or tungsten creating heat and radiating infrared terahertz rays.
7. The H- ion near the nucleus of the nickel atom loses electrons and becomes a free proton.
8. This proton can react with other nuclei, causing more reactions. Interaction with lithium atoms results in the creation of alpha particles.
9. Alpha particles grab electrons to create helium, creating heat from kinetic energy as the particles are absorbed.
10. Low-energy X-rays could create electricity from a photoelectric effect.