A shorted membrane electrochemical cell powered by hydrogen to remove CO2 from the air feed of hydroxide exchange membrane fuel cells

The alkaline environment of hydroxide exchange membrane fuel cells (HEMFCs) potentially allows use of cost-effective catalysts and bipolar plates in devices. However, HEMFC performance is adversely affected by CO 2 present in the ambient air feed. Here, we demonstrate an electrochemically driven CO 2 separator (EDCS) to remove CO 2 from the air feed using a shorted membrane that conducts both anions and electrons. This EDCS is powered by hydrogen like a fuel cell but needs no electrical wires, bipolar plates or current collectors, and thus can be modularized like a typical separation membrane. We show that a 25 cm 2 shorted membrane EDCS can achieve >99% CO 2 removal from 2,000 standard cubic centimetres per minute (sccm) of air for 450 hours and operate effectively under load-following dynamic conditions. A spiral-wound EDCS module can remove >98% CO 2 from 10,000 sccm of air. Our technoeconomic analysis indicates a compact and efficient module at >99% CO 2 removal costs US$112 for an 80 kW net HEMFC stack. Hydroxide exchange membrane fuel cells (HEMFCs) can make use of some relatively cheap components due to their alkaline environment, but face the problem of CO 2 in the air feed impeding performance. Here, the authors demonstrate a hydrogen-powered shorted electrochemical cell that effectively removes CO 2 from air streams for use in HEMFCs.