Green preparation of highly alkali-resistant PTFE composite membranes for advanced alkaline water electrolysis

Abstract To prepare a hydroxide ion conduction membrane with highly alkaline resistance for advanced alkaline water electrolysis, a large-scale and green preparation strategy that pore-filling polytetrafluoroethylene (PTFE) membrane is proposed to fabricate robust alkaline composite membranes, simultaneously enhance the interfacial compatibility between catalyst layer and membrane in membrane electrode assembly (MEA). Upon the rational design, the PTFE/layered double hydroxide (LDH) composite membranes exhibit good hydroxide conductivity, excellent wettability and exceptional alkaline stability, especially showing no change of the area resistance during 2000 h test in 1 M KOH solution at 60 °C. In advanced alkaline water electrolysis, the MEA with PTFE/LDH composite membranes and precious group metal-free (PGM-free) catalysts specifically showed the voltage of 1.8 V at the current density of 1 A cm−2, while that of commercial Fumasep FAA-3–50 membrane was 2.15 V. The long-term stability is conducted at a current density of 500 mA cm−2 for 180 h. Such performance with low-cost and mass-produced PTFE/LDH composite membranes demonstrates that the large-scale and green preparation strategy may drive the development of membranes for advanced alkaline water electrolysis.