Efficient and durable porous Membrane-Based CO₂ electrolysis for commercial Zero-Gap electrolyzer stack systems

This study presents a low-cost CO₂ electrolysis stack utilizing a porous-membrane exhibiting good performance and durability. The membrane electrode assembly (MEA), configuration, composed of an Ag cathode, IrO₂ anode, and polyvinylidene fluoride (PVDF) porous membrane, was optimized through various single-cell studies. To optimize the process for increasing the area of the reduction electrode, the characteristics of the spray coating method and the electron beam irradiation technology were compared. The Ag electrode fabricated through the e-beam process, exhibited diminished CO₂ reduction performance due to low porosity and high carbon monoxide (CO) affinity. A large-scale four-cell CO₂ electrolyzer stack (total area: 100 cm²) demonstrated CO mass production with over 80 % selectivity during 110-hour operation at 200 mA cm⁻². Moreover, CO production rate was reported as 7.28 L/h, equivalent to 5.63 kWh kg⁻¹ of electricity. Notably, this CO₂ electrolysis stack exhibits superior performance and durability compared to previous non-ion-exchange membrane separators reported, offering promising prospects for cost reduction and commercial scaling.