Insights into the Impact of Neutral Plates on Hydrogen and Oxygen Production in a One-Compartment Water Electrolyzer

Abstract

The environmental crisis driven by greenhouse gas emissions necessitates the exploration of alternative energy solutions to support the energy transition. Among these, palliative approaches are essential to mitigate the impact of fossil fuel-powered combustion engines. One promising, yet debated approach is hydrogen-assisted combustion. Although the use and study of low-cost electrolyzers have increased in recent years, questions remain, particularly regarding the role of neutral plates in one-compartment electrolyzers. This study investigates the impact of neutral plates on hydrogen and oxygen production within a one-compartment alkaline water electrolyzer equipped with stainless steel electrodes. Using NaHCO3-based electrolytes, we analyzed hydrogen and oxygen evolution through half-cell and electrolyzer measurements across various configurations with 6, 8, and 10 neutral plates. Our findings indicate that reducing the number of neutral plates enhances current density and gas flow, thereby improving efficiency. Electrochemical impedance spectroscopy revealed that neutral plates act as capacitors, increasing the overall resistance. Additionally, we observed that electrolyte conductivity significantly affects performance, with tailored electrolyte conductivity offering a method to control the output current density and temperature. Long-term electrolysis (∼15 days) tracking demonstrated that low-cost, one-compartment electrolyzers can reliably produce hydrogen and oxygen at a stable composition, suggesting their potential as an option for optimizing liquid petroleum gas and other fossil fuel combustion processes in the energy transition. This study provides valuable insights into one-compartment, cost-effective electrolyzers, highlighting pathways for enhancing the performance. These advancements could enable the development of affordable and scalable systems for pure hydrogen production by integrating oxygen trapping and hydrogen separation technologies.