Corrections of Voltage Loss in Hydrogen-Oxygen Fuel Cells

Abstract

Normally, the Nernst voltage calculated from the concentration of the reaction gas in the flow channel is considered to be the ideal voltage (reversible voltage) of the hydrogen-oxygen fuel cell. The Nernst voltage loss in fuel cells in most of the current literature is thought to be due to the difference in concentration of reaction gas in the flow channel and concentration of reaction gas on the catalyst layer at the time as when the high net current density is generated. Based on the Butler–Volmer equation in the hydrogen-oxygen fuel cell, this paper demonstrates that Nernst voltage loss caused by concentration difference of reaction gas in the flow channel and reaction gas on the catalyst layer at equilibrium potential. According to the relationship between the current density and the concentration difference it can be proven that Nernst voltage loss does not exist in hydrogen-oxygen fuel cells because there is no concentration difference of reaction gas in the flow channel and on the catalytic layer at equilibrium potential when the net current density is zero.

Deciphering electrochemical interactions in metal–polymer catalysts for CO2 reduction

“…S4, ESI†), indicating that PTFE scarcely affect the equilibrium reactant concentration on the cathode. 46 These results further underscore that the conventional understanding ( i.e. , PTFE alters CO 2 surface coverage) falls short in explaining the reagent distributions governed by steric effects.…”

Investigation of the Effect of Operating Parameters on Nernst Voltage in Hydrogen-Oxygen Fuel Cells

“…Since the entropy change of the H2/O2 reaction is negative, the Nernst voltage of H2/O2 fuel cells decreases with an increase in temperature of 0.84 mV/ºC (Çavuşoğlu 2006). There are other studies in the literature where it is observed that the fuel cell Nernst voltage decreases with increasing temperature (Arıç et al, 2019;Lyu et al, 2020;Outeiro et al, 2008;Riad et al, 2023;Sahli et al, 2017;Şefkat and Özel, 2018).…”

“…As seen in Figure 6, the Nernst voltage increases with the increase of anode pressure for both the HHV case and the LHV case, but this increase gradually decreases. There are other studies in the literature stating that increasing pressure positively affects fuel cell Nernst voltage (Arıç et al, 2019;Lyu et al, 2020;Nascimento et al, 2020).…”

“…Matsui et al (2005) emphasized that open circuit voltage in medium temperature solid oxide fuel cells (SOFCs) depends on electrode activity and electrolyte thickness, and overpotential at electrode/electrolyte interfaces affects OCV due to internal short circuit. In another study, Lyu et al (2020) divided the voltage losses that cause the Nernst voltage drop in the hydrogen-oxygen fuel cell into three categories and said that the concentration loss does not cause the Nernst voltage loss.…”