Fully anhydrous HCl electrolysis using polybenzimidazole membranes

We demonstrate for the first time a fully anhydrous gas-phase hydrogen chloride electrolyzer. By taking advantage of polybenzimidazole's (PBI) low membrane resistivity in anhydrous conditions (0.87 ± 0.57 Ω-cm2 at 160 °C) and its temperature and acid environment stability, we are able to directly convert pure hydrogen chloride gas to dry hydrogen and dry chlorine at efficiencies nearing 100% at an electrolyzer temperature of 160 °C and electrolyzer potential of 1.8 V. Finally, we discuss steps to further improve this electrolysis process in terms of both electrolyzer performance and cost reduction.