Multilayer CO2 Electrolyzer Stack Using Reinforced Sustainion® AEM

An ACS Energy Paper presents a zero gap electrolyzer cell and stack, which continuously converts gas phase CO2 to products without using any liquid catholyte. This is the first report of a multi layer CO2 electrolyzer stack for scaling up the electrolysis process.

The stack contained up to three electrolyzer layers (having 61 cm2 /stack active area). However, a PTFE reinforced Sustainion® (grade T) membrane was used to withstand pressurized CO2 gas intake (up to 10 bar). The grade T Sustainion® has at-least twice the impact strength and a much higher tensile strength than its unsupported version but boasts a similar ionic conductivity. Hence, it was an essential ingredient considering the pressurized system.

Furthermore,15% XA-9 Sustainion® Ionomer was used stabilize the Ag cathode ink and improve the triple phase boundary. The setup is shown below.

Fig. 1: Serial connectionconfigurations of the stack. The AEM at the heart of the MEA was Sustainion® (grade T) membrane and the ionomer was XA-9 Sustainion®.

CO formation with partial current densities above 250 mAcm−2 were achieved routinely, which was further increased to 300mA cm−2 (with ∼95% faradic efficiency) with help of the grade T Sustainion® membrane by pressurizing the CO2inlet (up to 10 bar). Evenly distributing the CO2 gas among thelayers, the electrolyzer operates identically to the sum of multiplesingle-layer electrolyzer cells. When passing the CO2 gas throughthe layers consecutively, the CO2 conversion efficiency increased.

To take advantage of the highly conductive yet robust grade T Sustainion® AEM and XA-9 Sustainion® Ionomer along with full CO2 electrolyzers and parts, visit the Dioxide Materials webstore and place an order.