Faraday-efficiency effect
Encyclopedia
The Faraday-efficiency effect refers to the potential for misinterpretation of data from experiments in electrochemistry
through failure to take into account a Faraday efficiency
of less than 100 per cent.
of water has always a Faraday efficiency of 100%. Pons and Fleischmann, and other investigators who reported the finding of anomalous excess heat
in electrolytic cells, all relied on this popular assumption. No one bothered to measure the Faraday efficiency in their cells during the experiments. Many publications reporting the finding of excess heat included an explicit statement like: "The Faraday efficiency is assumed to be unity." Even if not explicitly stated so, these publications included this assumption implicitly in the formulas used to calculate the cells' energy balance.
and Fleischmann
to cold fusion
. Later, it was discovered that such excess heat can easily be the product of conventional chemistry, i.e. internal recombination of hydrogen and oxygen. Such recombination leads to a reduction in the Faraday efficiency of the electrolysis. The Faraday-efficiency effect is the observation of anomalous excess heat due to a reduction in the Faraday efficiency.
s which included the capability to measure the actual Faraday efficiency in real time during the experiments. The cells were of the light-water type; with a fine-wire nickel cathode; a platinum anode; and K2CO3 electrolyte.
The calorimeters were calibrated to an accuracy of 0.02% of input power. The long-term stability of the calorimeters was verified over a period of 9 months of continuous operation. In their publication, the investigators show details of their calorimeters' design and teach the technology of achieving high calorimetric accuracy.
Jones et al. have confirmed the Shkedi et al. findings with the same conclusion:
Electrochemistry
Electrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...
through failure to take into account a Faraday efficiency
Faraday efficiency
Faraday efficiency describes the efficiency with which charge are transferred in a system facilitating an electrochemical reaction. The word "faraday" in this term has two interrelated aspects...
of less than 100 per cent.
Assumption about efficiency
Until recent decades it was common to assume that the release of hydrogen and oxygen gas during electrolysisElectrolysis
In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...
of water has always a Faraday efficiency of 100%. Pons and Fleischmann, and other investigators who reported the finding of anomalous excess heat
Cold fusion
Cold fusion, also called low-energy nuclear reaction , refers to the hypothesis that nuclear fusion might explain the results of a group of experiments conducted at ordinary temperatures . Both the experimental results and the hypothesis are disputed...
in electrolytic cells, all relied on this popular assumption. No one bothered to measure the Faraday efficiency in their cells during the experiments. Many publications reporting the finding of excess heat included an explicit statement like: "The Faraday efficiency is assumed to be unity." Even if not explicitly stated so, these publications included this assumption implicitly in the formulas used to calculate the cells' energy balance.
Relevance to cold fusion
Lacking any other plausible explanation, the anomalous excess heat produced during such electrolysis was attributed by PonsStanley Pons
Bobby Stanley Pons is an American-French electrochemist known for his work with Martin Fleischmann on cold fusion in the 1980s and '90s.-Early life:...
and Fleischmann
Martin Fleischmann
Martin Fleischmann is a British chemist noted for his work in electrochemistry. He came to wider public prominence following his controversial publication of work with colleague Stanley Pons on cold fusion using palladium in the 1980s and '90s.-Early life:Born in Karlovy Vary, Czechoslovakia,...
to cold fusion
Cold fusion
Cold fusion, also called low-energy nuclear reaction , refers to the hypothesis that nuclear fusion might explain the results of a group of experiments conducted at ordinary temperatures . Both the experimental results and the hypothesis are disputed...
. Later, it was discovered that such excess heat can easily be the product of conventional chemistry, i.e. internal recombination of hydrogen and oxygen. Such recombination leads to a reduction in the Faraday efficiency of the electrolysis. The Faraday-efficiency effect is the observation of anomalous excess heat due to a reduction in the Faraday efficiency.
Measurement
A group of investigators, headed by Zvi Shkedi, from Massachusetts, USA, built in 1991-1993 well-insulated cells and calorimeterCalorimeter
A calorimeter is a device used for calorimetry, the science of measuring the heat of chemical reactions or physical changes as well as heat capacity. Differential scanning calorimeters, isothermal microcalorimeters, titration calorimeters and accelerated rate calorimeters are among the most common...
s which included the capability to measure the actual Faraday efficiency in real time during the experiments. The cells were of the light-water type; with a fine-wire nickel cathode; a platinum anode; and K2CO3 electrolyte.
The calorimeters were calibrated to an accuracy of 0.02% of input power. The long-term stability of the calorimeters was verified over a period of 9 months of continuous operation. In their publication, the investigators show details of their calorimeters' design and teach the technology of achieving high calorimetric accuracy.
Experiments
A total of 64 experiments were performed in which the actual Faraday efficiency was measured. The results were analyzed twice; once with the popular assumption that the Faraday efficiency is 100%, and, again, taking into account the measured Faraday efficiency in each experiment. The average Faraday efficiency measured in these experiments was 78%.First analysis
The first analysis, assuming a Faraday efficiency of 100%, yielded an average apparent excess heat of 21% of input power. The term "apparent excess heat" was coined by the investigators to indicate that the actual Faraday efficiency was ignored in the analysis.Second analysis
The second analysis, taking into account the measured Faraday efficiency, yielded an actual excess heat of 0.13% +/- 0.48%. In other words, when the actual Faraday efficiency was measured and taken into account, the energy balance of the cells was zero, with no excess heat.Conclusion
This investigation has shown how conventional chemistry, i.e. internal recombination of hydrogen and oxygen, accounted for the entire amount of apparent excess heat. The investigators concluded their publication with the following word of advice:
"All reports claiming the observation of excess heat should be accompanied by simultaneous measurements of the actual Faraday efficiency."
Jones et al. have confirmed the Shkedi et al. findings with the same conclusion:
"Faradaic efficiencies less than 100% during electrolysis of water can account for reports of excess heat in 'cold fusion' cells."