Bioinspired Spatially Topological Strategy Boosts the Anion Exchange Membrane for Industrial-scale Water Electrolysis

The transport of ions through the anion exchange membrane (AEM) depends on the overall energy barriers imposed by the collective interplay of ion channel architecture. The efficient transport of water and ions can be observed ubiquitously in plants. Inspired by the pectin in nature, we developed a spatially topological strategy for designing high-performance AEMs. To achieve precision control at the molecular level, several spatially topological molecules such as triptycene and 9,9’-spirobifluorene were utilized as single or dual framework centers for the anion exchange membrane. By manipulating the ratio of triptycene and 9,9’-spirobifluorene in the polymer, a high ionic conductivity (197.4 mS cm-1 at 80 °C) and an exceedingly low swelling ratio (8.6% at 80 °C) can be attained. The present AEM-WEs achieved a new record high current density of 8.4 A cm−2 at 2.0 V with a 1 M KOH at 80 °C using platinum group metal (PGM)-free catalysts, which surpassed that of state-of-the-art proton exchange membrane water electrolyzers (PEM-WEs) (~ 6 A cm−2 at 2.0 V) and operated stably at a current density of 2 A cm−2 with a cell voltage of 1.8 V for more than 600 h at 60 °C. Notably, when we used the cell with five stacked PGM-free based membrane (T4-1.0-0.5, 80 μm) electrodes, a hydrogen production rate of 0.54 Nm3 h−1 was achieved. The industrial system demonstrates a high level of efficiency and stability while operating under working conditions with a current density of 1 A cm-2 at 2 V

What We Can Learn from Watermelon Skin for the Design of Artificial Ion-Transport Membranes

Selective ion-transport membranes (ITMs) are core components of electrochemical energy conversion and storage devices. However, the development of low-ion-resistance and high-ion-selectivity transport membranes still poses challenges. To propose effective design strategies for achieving high performance ITMs, this work conducted a deep exploration of watermelon skin membranes (WSMs) obtained by the freezing-exfoliation method through a combination of experimental research and molecular dynamics simulation. The micropores and continuous hydrogen-bonding network constructed by the synergistic effect of cellulose fiber and pectin enables WSM to have an ion conductivity of 235.2 mS cm-1 (RT). The negatively charged groups and many hydroxyl groups modified on the surface of the microporous channels enhance the formate penetration resistance of WSMs by 12.8 times compared to that of commercial Fumasep membranes. Therefore, the Confinement of proton donor and negatively charged group-enriched microporous polymers within three-dimensional framework systems is expected to become a new design strategy for high-performance ITMs