Mizuno's technology while stunning is the equivalent of what Rossi was working on before his first public test. Rossi moved forward from there, testing a wide array of different configurations and optimizations. He soon learned that there were other ways to produce atomic hydrogen to dramatically accelerate the absorption process into the nickel. Electrical discharges, radio frequency generators, the use of of LiAlH4 (the gas that is emitted is atomic before recombining), and other methods allowed him to improve upon his first devices. Eventually, he started working on pure plasma based devices after he and other parties observed "creatures of light" within his reactors that used three phase AC power that created rotating magnetic fields (ideal for spinning up plasma). I remember a few of the names were E-Cat X, Madam Curie, QX, SK, etc. These all had one common feature - they utilized the negative resistance regime of an electrical discharge to create a self organizing "complex space charge configuration" or macro-EVO. I'm guessing his first systems only produced transitory EVOs in a method similar to Kenneth Shoulder's original system. Later, I think he probably discovered that you could create a stable macro-EVO. These go through three stages. First, the complex space charge configuration is formed with an interior of positive ions and an exterior of electrons. A double layer of positive ions and negatively charged electrons protect the structure like a cellular membrane. Second, further self-organization takes place and the CSCC starts absorbing energy and matter from the plasma environment and converting it into electrical current. During this stage, the CSCC remains tethered to the electrode. Finally, the last step of self organization takes place and the CSCC detaches from the electrode.
My guess is that he has been able to optimize the self organization of the CSCC by resonantly tuning the circuit and adding heavier elements such as Argon in addition to hydrogen or deuterium.
I think another level will be using additional isotopes that can be spin polarized like 199Hg or silver.
Rossi can defrost him on top of the e-cat SK LdC and supply drinking water to third world children.