The LEC, the CPD, and Dr. Chang the Zombie Hunter.

A fascinating read, Hasok Chang (the most engaging company btw) has looked deep into the long standing and still prevailing confusion about the phenomenon known as 'Contact Potential Difference'. This is the mechanism which Frank Gordon and Harper Whitehouse believe lies at the heart of the LEC phenomenon - as do I. The LEC is based on the amplification of this effect seen, sometimes discussed, sometimes dismissed, then revived again going back over several centuries- back to the work of Volta in fact.

Wikipedia says "The Volta potential (CPD) is seen when two different neutral metal surfaces are brought into electrical contact (even indirectly, say, through a long electro-conductive wire), electrons will flow from the metal with the higher Fermi level to the metal with the lower Fermi level until the Fermi levels in the two phases are equal. Once this has occurred, the metals are in thermodynamic equilibrium with each other (the actual number of electrons that passes between the two phases is usually small). Just because the Fermi levels are equal, however, does not mean that the electric potentials are equal. The electric potential outside each material is controlled by its work function, and so dissimilar metals can show an electric potential difference even at equilibrium. The Volta potential is not an intrinsic property of the two bulk metals under consideration, but rather is determined by work function differences between the metals' surfaces. Just like the work function, the Volta potential depends sensitively on surface state, contamination, and so on."

Dr Chang says.

-

"Argument
Much of the long controversy concerning the workings of electric batteries revolved around the concept of the contact potential (especially between different types of metals), originated by Alessandro Volta in the late eighteenth century. Although Volta’s original theory of batteries has been thoroughly rejected and most discussions in today’s electrochemistry hardly ever mention the contact potential, the concept has made repeated comebacks through the years, and has by no means completely disappeared. In this paper,
I describe four salient foci of its revivals: dry piles, thermocouples, quadrant electrometers, and vacuum phenomena. I also show how the contact potential has maintained its presence in some cogent modern scientific literature. Why has the death of the Voltaic contact potential been such an untidy affair? I suggest that this is because the concept has displayed significant meaning and utility in various experimental and theoretical contexts, but has never been successfully given a simple, unified account. Considering that situation, I also suggest that it would make sense to preserve and develop it as a multifarious concept."

Read and enjoy. I think that the work of Gordon and Whitehouse ( Stevenson plus Matt Lilley and mine) shows that there are ways in which the Volta potential can be enhanced and made more durable.. Notice that comment from Wikipedia's piece "the Volta potential depends sensitively on surface state, contamination, and so on."

dead-or-undead-the-curious-and-untidy-history-of-voltas-concept-of-contact-potential.pdf

Quote from Curbina

So, just to be clear, this is chemistry after all? Or this has been nuclear all the time, staring at our face, and we just did not realize until now? Or we still don’t know?

Not at all - this is the migration of electrons - either directly or by piggybacking onto ions from one place to another, from somewhere with a high concentration of electrons, to somewhere with less.

ETA - from Dr. Chang's paper.

"

Langmuir offered a unified view of relevant phenomena as much as possible, making use of the
concept of different degrees of “electron affinity” that different metals have (see Table IV on
Langmuir [1916] 1961, 198, which shows the values of electron affinity estimated through five
types of phenomena). The consilience of experimental data suggested that “contact potential,
photo-electric effect and thermionic emission, are thus shown to be intimately related to each
other”. All three phenomena hinge directly on electron affinity, “a quantitative measure of the
work done in separating electrons from the metal”. Langmuir was confident that in each case
experimental evidence showed that the core effect was not chemical, though chemical reactions
did certainly add other effects. Moreover, the evidence of independence from chemistry concerning one phenomenon also constituted the same for the other phenomena, since they were ultimately the same: “Because of the relationships between the different phenomena, a proof that
any one of them is not caused by chemical action must be considered to be proof that none
of them is so caused”"

The LEC is a CPD based device, no argument. But CPD systems rapidly run down as the available free electrons equilibrate. What co-dep and/or hydrogen loading does with the LEC is modify the surface of the working electrode so it generates extra electrons. And so long as you can avoid corrosion, they do not rapidly equilibrate but go on producing current for a long time. I have a brass/brass one in my lab that is 8 months old - 2 plates in air- no co-dep, hydrogen loaded with a carbon anode. Still producing 15mV despite being shorted out the whole time.

Hi Jed. We are looking at a surface-based phenomenon si area is key. I'll measure it tomorrow. I think we can do an estimate.

@THH. If you wish I can weigh it while you try to work out a chemical reaction between brass alloy and hydrogen. Take your time.

Plate area for both brass electrodes is 24 cm² each. Reasonable estimates for total power output over 5250 hours approx is between a low of 10Wh and a high of 20wH.

While this figure is low these 2 plates have not been stored optimally, having been stacked face-to face in a box for most of the 5250 hours since creation. That this affects performance is shown by the fact that it takes around 10 minutes in an optimal configuration with a nylon mesh spacer (.01mm thick approx) for the voltage to recover to today's figure of 14mV and 10 microamps.

These plates were produced as part of an attempt to debunk ideas about thermocouple effects, the need for co-dep etc. So cut from the same sheet of brass and the working electrode electrolysed with a carbon rod anode in K2C03. Worth pointing out that brass is not considered to be readily loaded with hydrogen by electrolysis. And they have been stored in air so leaching out H2 all the time. So this is far from an optimal system -but it's still working . Put simply, I tried everything I could to produce a bad system, but it still worked.

Extracts from this paper https://www.sciencedirect.com/…abs/pii/S092583880401196X

show that Brass (Cu70/Zn30) is not an ideal material if you are interested in hydrogen loading.

Experimental method

The material used in this study was obtained from an α-brass (70 wt.% Cu–30 wt.% Zn) sheet with 1 mm thickness. A number of microhardness (3 cm × 1 cm) and standard tensile specimens were made from this sheet. The stress relief procedure was performed by annealing the specimens at 275 °C for 30 min and slowly cooling at room temperature, in an Ar-inert atmosphere. After annealing of the α-brass specimens, the central portion of each specimen was electropolished. This process took place in a 60 vol.% H₃PO₄

Results and discussion

X-ray diffraction (XRD) investigations, performed on the hydrogen charged α-brass specimens were unable to detect secondary phases, e.g. hydrides. This observation leads to the assumption that, either hydrides were not formed on the surface layers of hydrogen charged α-brass specimens, or the concentration of the formed hydrides was very small and therefore undetectable from the XRD. On the contrary, the diffraction peaks corresponded only to copper,The following conclusions of the present study can be given:

• 1.

  Hydride was not observed with the XRD technique, either because of its absence, or its very low concentration in the charged α-brass surface layers.

• 2.

  The microhardness of the hydrogen charged α-brass surface layers was observed to increase significantly with increasing charging time for a constant value of current density or with increasing current density for a constant value of charging time.