Modified Szpak Protocol for Excess Heat
Dennis Letts · Peter L. Hagelstein
Abstract and summary · read the original at the source
In one page
Dennis Letts and Peter Hagelstein start from a piece of theory and follow it into the cell. Excess heat in a Fleischmann–Pons experiment, on their reading, needs molecular deuterium sitting inside the palladium, and that can only form where a palladium atom is missing — a vacancy. Vacancies only become favourable once the deuterium-to-palladium ratio reaches about 0.95, which is why the original experiment demands weeks of hard electrochemistry and disappoints so often. Their conclusion is that the classic experiment works partly by accident: palladium and stray impurities plate back onto the cathode at high loading, and that thin outer layer is where the vacancies, and the heat, live. If that is right, the sensible move is to plate on purpose, which is the Szpak co-deposition experiment. That one has been hard to replicate too, and the authors blame low loading, since Szpak’s recipe must run at low current or the palladium will not stick. Their fix is to cut the palladium concentration and raise the current hard.
Why it matters hereChapter 12 is about getting deuterons close enough together inside a metal lattice for tunnelling to matter, and this paper puts a specific, buildable answer on the table for why that condition is so hard to reach and what to change in the recipe to reach it reliably. It is a chapter 1 sheet as much as a chapter 12 one: a calibrated Seebeck calorimeter checked before every run, an inert titanium cathode as the in-cell null, a matched light-water control, and an endotherm the authors chase down to a chemical reaction rather than leaving it as noise. The Szpak co-deposition method it modifies is on the site at /library/stm-344232fcb0, and Szpak’s own thermal measurements at /library/stm-f6651a4d1a.
What it claims
01Hydrogen stabilises vacancies in palladium: a monovacancy costs on the order of one electronvolt in pure palladium, but adding hydrogen or deuterium lowers that cost so far that near room temperature and a loading of 0.95 the lattice would find a lower energy by rearranging into a phase with about a quarter of the palladium sites vacant — the superabundant vacancy phase Fukai and Okuma produced as Pd0.75H.Section 2, Vacancies; Figure 1
Published and peer-reviewed02The mechanism the authors work from is that molecular deuterium cannot form in bulk palladium deuteride because the electron density is too high — about 0.08 electrons per cubic angstrom at the octahedral sites against the roughly 0.033 a sigma-bonded molecule needs — while next to a vacancy it can, which is why loading and loading time are the two requirements the SRI campaign kept running into.Section 2, Vacancies; Section 1 on the SRI thresholds of 0.95 peak loading and 2 to 4 weeks
What to watch03The classic Fleischmann–Pons cell is read as working through inadvertent co-deposition: elemental analysis finds platinum and other impurities in the outer 100 to 300 nanometres of the cathode, palladium is plating there too, and if that happens at a loading of 0.95 or above then the co-deposited layer carries superabundant vacancies — consistent with helium being found in the gas phase, since helium made deeper than a micron would stay in the lattice.Section 2, closing paragraphs
What to watch04Their diagnosis of why the Szpak experiment resists replication is the current density: loading rises with current, but Szpak’s 0.05 molar palladium chloride will not adhere at high current, so the protocol is forced to run low and the loading needed to stabilise vacancies is often never reached.Section 3, Codeposition and the Szpak Experiment; Section 11, Discussion
What to watch05The modified protocol reverses that trade: a copper substrate gold-plated for five minutes, 0.15 molar lithium chloride in 100 grams of 99.9 percent heavy water, and palladium at 0.00125 molar — one fortieth of Szpak’s concentration — co-deposited at about 500 milliamps per square centimetre. Adhesion improved, bridging stopped, and excess power was observed in every experiment run with the protocol.Section 4, Modified Szpak Protocol at High Current Density; Section 11
On the bench now06In experiment 684d the cell held power balance to within 1 percent on the inert titanium cathode, then produced 250 milliwatts of excess power the moment electrolysis was switched to the gold-plated copper cathode, for about 7 kilojoules of excess energy and a 4 to 5 degree rise in cell temperature, with the signal decaying over nine hours once the heavy-water electrolyte was pumped out and replaced with light water; experiment 685 recovered about 110 kilojoules with no sign of diminishing over 60 hours, and the matched pair 690a and 691d gave a 4 kilojoule exotherm in heavy water against a 529 joule endotherm in light water that the authors traced to hypochlorous acid formation with a calculated enthalpy of 503 to 555 joules.Sections 8, 9 and 10; Figures 7, 8 and 9
Published and peer-reviewed
Read it · abstract
Abstract
In recent theoretical work, vacancies in PdD have been shown to be able to host molecular D2, which is conjectured to be necessary for excess heat in Fleischmann–Pons experiments. Vacancies in the original Fleischmann–Pons experiment are proposed to be created through inadvertent codeposition at high loading. This suggests that a better approach should be to focus on experiments in which Pd codeposition is controlled, such as in the Szpak experiment. Unfortunately, the Szpak experiment has proven difficult to replicate, and we conjecture that this is due to low D/Pd loading. A modified protocol has been tested in which codeposition is carried out at higher current density with a lower PdCl2 concentration. Positive results have been obtained in all of the tests done with this protocol so far.
Dennis Letts, Austin, Texas; Peter L. Hagelstein, Research Laboratory of Electronics, MIT. Journal of Condensed Matter Nuclear Science 6 (2012) 44–54.
(Abstract only. The complete article is free to read at https://jcmns.org/article/72159.pdf and via https://doi.org/10.70923/001c.72159 — see the rights note for why the full text is not reproduced here.)
The way in
https://doi.org/10.70923/001c.72159Published as J. Condensed Matter Nucl. Sci. 6 (2012) 44 to 54, as a Research Article. Licence checked directly in the article rather than taken from an aggregator label: the paper carries the line ‘© 2012 ISCMNS. All rights reserved’ twice, on the title page and at the foot of the first page, and no Creative Commons statement, so this page carries the summary, the claims and the authors’ own abstract and sends the reader to the source. The complete article is free to read at the journal, jcmns.org/article/72159.pdf. The summary and claims below were written from the full published text. The work was partly supported by DTRA under contract N0 017308P2015.
How to cite it
Dennis Letts, Peter L. Hagelstein (2012) Modified Szpak Protocol for Excess Heat. doi:10.70923/001c.72159
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