A 3D nanofiber network anode expediting mass and proton transport to boost proton exchange membrane water electrolysis

The key to promote the performance of proton exchange membrane water electrolysis (PEMWE), in addition to the development of high-performance electrocatalysts, lies in how to rationally design and controllably construct nanostructured membrane electrode assembly (MEA) with a maximized triple-phase reaction boundary (TPRB). Herein, a novel 3D nanofiber network (3D-FNT) anode is controllably fabricated via electrospinning combined with a nano-transfer strategy. This novel MEA can dramatically lower the IrO2 loading from 1.0 to 0.1 mg cm-2 while ensuring a superior performance (1.737 V@1.5 A cm-2) together with an impressive stability, and outperforms the most reported nanostructured MEAs to date. Electrochemical impedance spectroscopies elucidate that both the 3D network and 1D Nafion channels improve mass transport and proton conduction by 1.34 and 7.76 fold, respectively, compared with the traditional MEA, shedding light on the performance enhancement mechanism. This work paves a way to defuse the cost and performance issues confronting practical PEMWE. A 3D nanofiber network anode accelerates mass and proton transfer simultaneously, affording superior activity (1.737 V@1.5 A cm-2) and excellent stability over 200 h for a MEA with an IrO2 loading of ca. 0.1 mg cm-2.