This is video from LENR Forum in which Ruby Carat and David Nygren speak with Alan Smith about the Lattice Energy Converter (LEC), which had been developed by Frank Gordon, and has been replicated by various other experimenters.
Gordon has found that when two treated metal plates (Alan says iron works well) are separated by a small gap a voltage is detected. Alan states that this system works in air for a time, but over time the plates oxidize, so the running the experiment in a hydrogen atmosphere can prevent oxidization, and the effect can be seen for a period of months.
So far they have only built small systems in terms of surface area, with 200-400 millivolt, and the currents are small, but Alan states “they should not be there”. It is too early to tell is if it can be practical; he says it needs to be experimented with to see if it can be scaled up.
Alan estimates there have been seven replications of this so far.
Alan shows an experiment on camera and at first it does not work, but later he gets it to work and detects the expected voltage.