Lab-Scale Alkaline Water Electrolyzer for Bridging Material Fundamentals with Realistic Operation

Abstract

Hydrogen produced by water electrolysis with renewable electricity is a reliable, affordable and environmental friendly energy carrier for future energy supply and storage. Alkaline water electrolysis is a well matured technique and proved to be suitable for large-scale applications. Materials development for alkaline water electrolyzers is still of interest for academia and industry to address the issues of low compatibility to renewable power sources. A lab-scale system for alkaline water electrolysis was developed, aiming to advance materials development and to bridge the intrinsic properties of materials with their performance under realistic operating conditions. As the smallest pressure-type electrolyzer, it is capable of working at 30 bar and 80 °C with continuous liquid electrolyte circulation. Experimental studies investigate the influence of temperature, pressure, and intrinsic properties of materials on voltage efficiency and hydrogen purity. With appropriate analysis, links between material specifications and overall performance can be established, encouraging new designs and material innovations for alkaline water electrolysis.

Green hydrogen from anion exchange membrane water electrolysis: a review of recent developments in critical materials and operating conditions

“…57 Indeed, carbon is used as fuel at the anode for molten NaOH carbon air batteries. 57 On the cathode side carbon can be readily used, 54,55,111,113,119,120,123,124,126 as well as Ni 95,101,102,108,115,121,127,128 and Ti. 117,118 The electrode preparation method is predominantly based on spraying a catalyst ink over the activated support surface.…”

“…Concentrations above 20 mass% are used in AE together with ion solvating membranes 95,103,104,127 or diaphragm separators. 104,109,128 With anion exchange polymer membranes, concentrations can range from 3 to 10 mass%. [99][100][101]113,123,126,144 Generally, electrolysis performance improves with increasing concentration of the hydroxide solution.…”

“…Dilute carbonate or bicarbonate solutions have a mildly alkaline pH (10-12) that retains sufficient ionic conductivity. V using the CCM 57,59,106,107,114,116,[131][132][133][134][135][136][139][140][141] or CCS 22,54,55,95,[101][102][103][104]108,109,[111][112][113]115,[117][118][119][120][121][122][123][124][126][127][128][129]142,143 method of MEA construction. Additionally, such conditions should provide enhanced stability of cell materials as well as the polymeric AEM/binders.…”

“…The reason in this particular case lies probably in the type of the separator used. Highly concentrated KOH solutions are typically used when diaphragms 102,160 or ion solvating membranes 95,103,104,127 are utilized as the separator of the electrode compartments. In these cases, however, the current densities did not exceed 120 mA cm À2 .…”

Hydrogen production from industrial wastewaters: An integrated reverse electrodialysis - Water electrolysis energy system

“…Firstly, a pilot-scale RED unit was optimized for SGP generation using industrial waste streams: the performance of the RED unit was evaluated in terms of voltage and power density at varying flow velocity and temperature of waste streams. Next, a laboratory-scale APWEL system, scaled-up 6-fold compared to most cases studied using single-cell designs (Ju et al, 2018;, was tested for potential hydrogen production driven by SGP: the hydrogen production rate was evaluated at varying electrolyte concentrations and temperatures to identify optimal operating conditions. The ultimate goal was to demonstrate the possibility of converting the electrochemical potential of industrial waste streams into clean energy and hydrogen by an integrated RED-APWEL energy system.…”