High Performance Evaluation of a Cylindrical Two-Cell Ni Foam-Based Alkaline Electrolyser Stack Under Different Operating Conditions

The production and utilization of hydrogen through electrolysis using affordable and easily designed electrode materials have been a primary interest and are considered essential for clean and sustainable energy systems. In this study, a newly developed cylindrical two-cell, membraneless alkaline electrolyser stack using nickel foam electrodes as anodes and cathodes was achieved and experimentally investigated to evaluate hydrogen production performance under different operating conditions. This unique configuration offers a compact stack design, differing from traditional planar single-cell electrolyser systems. To provide a comprehensive performance assessment, hydrogen production behavior was systematically investigated along with Faradaic efficiency, specific energy consumption (SEC), and energy-exergy efficiencies. After 300 minutes of electrolysis, a maximum hydrogen volume of 7630 mL was achieved at 4 V, 1 M KOH, and 55°C. However, considering energy efficiency metrics, the optimum operating conditions were determined to be 3 V applied voltage, 1 M KOH concentration, and 55°C, yielding 6569.9 mL of hydrogen. Increasing the applied voltage and operating temperature increases hydrogen production but also leads to a decrease in energy efficiency. Faradaic efficiency showed a limited change with voltage, and slightly higher values were observed under moderate operating conditions. The results show that a balanced assessment of hydrogen production and efficiency criteria is necessary for the effective operation of the electrolyser. This emphasizes that determining the optimum operating conditions is more meaningful than focusing only on maximum hydrogen production. The proposed cylindrical two-cell membraneless design, combined with nickel foam electrodes, provides a practical perspective for the development of efficient alkaline electrolysis systems.