Ordered Membrane Electrode Assembly with Drastically Enhanced Proton and Mass Transport for Proton Exchange Membrane Water Electrolysis

In this work, an ordered membrane electrode assembly(MEA) basedon a cone Nafion array with gradient Nafion distribution, tightlybonded catalytic layer/proton exchange membrane (CL/PEM) interface,and abundant vertical channels has been engineered by an anodic aluminumoxide template and magnetron sputtering method. Benefiting from ahighly efficient CL/PEM interface, plentiful proton transfer highways,and rapid oxygen bubble release, this ordered MEA achieves an ultralowIr loading of 20.0 & mu;g cm(-2) and a high electrochemicalactive area by 8.7 times compared to traditional MEA with Ir loadingof 1.0 mg cm(-2). It yields a mass activity of 168 000mA mg(Ir) (-1) cm(-2) at 2.0V, which is superior to most reported PEM electrolyzers. Notably,this ordered MEA maintains excellent durability at a current densityof 500 mA cm(-2). This work opens a simple, cost-effective,and scalable route to design ordered MEAs for proton exchange membranewater electrolysis.