Improved chloralkaline reversible electrochemical cells featuring a catalytic-coating-free 3-D printed titanium gas diffusion electrode

This study presents a novel resin 3-D printed chloralkaline reversible electrochemical cell featuring a 3-D printed titanium (3DP-Ti) cathode and a mixed-metal oxide anode. It evaluates the capability of this cell for electricity production (using hydrogen and bleach as fuel and comburent, respectively) and electrolysis of NaCl brine (producing hydrogen, chlorine, and retaining carbon dioxide). Parameters including NaCl concentration, bleach pH, and temperature were varied for examination. Despite the assembled 3DP-Ti does not contain any cathodic catalytic layer, the cell shows outstanding performance and it reaches maximum power densities of 7.38 mWcm(-2) and maximum current densities of 12.7 mAcm(-2). Hydrogen is flowed through small pores and electricity production dependence on feeding solution pH, electrolyte concentration, and temperature are observed. The system proved as a reversible chloralkaline electrochemical cell by confirming its good performance as an electrolyzer, with faradic efficiencies of 100 % for hydrogen production and 70 % for chlorine production. Energy efficiencies reached 196.54 mg Cl-2/Wh and 7.48 mg H-2/Wh. During operation as an electrolyzer (stream feeding to the gas diffusion cathode), it also demonstrated the capacity to fix carbon dioxide contained in gaseous streams by reacting with hydroxyl ions produced during the electrochemical hydrogen production. The fixation efficiency was 220.0 mg CO2 fixed/Wh. These findings demonstrate progress in electrochemical cell technology, highlighting its potential for various electrochemical applications.