Rational control of unidirectional proton transport is highly challenging, primarily owing to the difficulty in introducing an asymmetric factor into proton conducting media. In this study, free-standing membranes of a proton-conducting two-dimensional porous coordination polymer, Cu 2 (CuTCPP) (H 2 TCPP: 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin) and a hydroxide ion-conducting layered double hydroxide, Mg-Al-LDH(NO 3 ), were combined to generate a pH gradient in the conducting media. The current-voltage measurements revealed that the heterogeneous membrane exhibits a significant unidirectional proton transport with a proton rectification ratio exceeding 200 under 90 % relative humidity in the initial voltage scan. This value is the highest among the reported all-solidstate proton rectifiers. The high designability of both components with well-defined structures, which is in contrast to the organic polymers used so far, provides a new avenue for developing and understanding the proton-rectifying behavior in the solid state.

Introduction of mechanical flexibility into proton‐conducting coordination polymers (CPs) is in high demand for future protonic applications such as fuel cells and hydrogen sensors. Although such mechanical properties have been primarily investigated in one‐dimensional (1D) CPs, in this study, we successfully fabricated highly flexible free‐standing CP membranes with a high surface‐to‐volume ratio, which is beneficial for enhanced performance in the aforementioned applications. We fabricated a layered CP, Cu2(NiTCPP) (H4(H2TCPP); 5,10,15,20‐tetrakis(4‐carboxyphenyl) porphyrin), in which a two‐dimensional (2D) square grid sheet composed of tetradentate nickel porphyrins and paddlewheel‐type copper dimers was connected to each other by weak van der Waals forces. The mechanical flexibility was evaluated by bending and tensile tests. The flexural and Young's moduli of the membrane were significantly higher than those of conventional Nafion membranes. Electrochemical impedance spectroscopy analysis revealed that the in‐plane proton conductivity of the membrane was maintained even under applied bending stress. Because the X‐ray diffraction analysis indicates that the proton‐conducting pathway through the hydrogen bonding network remains intact during the bending operation, our present study provides a promising strategy for the fabrication of new and advanced 2D CPs without using substrates or additional polymers for protonic devices.

An all-solid-state proton rectifier … …, which was fabricated using ah eterogeneous membrane of ap rotonconducting coordination polymer,C u 2 (CuTCPP), and ah ydroxide-ion-conducting layered double hydroxide,M g-Al-LDH(NO 3 ), is presented by Yukihiro Yoshida, Hiroshi Kitagawa, and co-workers in their Research Article (e202213077). Thed evice demonstrated ap roton rectification ratio greater than 200, which is the highest among the reported all-solid-state H + -OH À rectifiers.

Introduction of mechanical flexibility into proton‐conducting coordination polymers (CPs) is in high demand for future protonic applications such as fuel cells and hydrogen sensors. Although such mechanical properties have been primarily investigated in one‐dimensional (1D) CPs, in this study, we successfully fabricated highly flexible free‐standing CP membranes with a high surface‐to‐volume ratio, which is beneficial for enhanced performance in the aforementioned applications. We fabricated a layered CP, Cu2(NiTCPP) (H4(H2TCPP); 5,10,15,20‐tetrakis(4‐carboxyphenyl) porphyrin), in which a two‐dimensional (2D) square grid sheet composed of tetradentate nickel porphyrins and paddlewheel‐type copper dimers was connected to each other by weak van der Waals forces. The mechanical flexibility was evaluated by bending and tensile tests. The flexural and Young's moduli of the membrane were significantly higher than those of conventional Nafion membranes. Electrochemical impedance spectroscopy analysis revealed that the in‐plane proton conductivity of the membrane was maintained even under applied bending stress. Because the X‐ray diffraction analysis indicates that the proton‐conducting pathway through the hydrogen bonding network remains intact during the bending operation, our present study provides a promising strategy for the fabrication of new and advanced 2D CPs without using substrates or additional polymers for protonic devices.

…, der aus einer heterogenen Membran aus protonenleitenden Koordinationspolymer,C u 2 (CuTCPP), und einem hydroxidionenleitenden Doppelhydroxid, Mg-Al-LDH(NO 3 ), hergestellt wurde,w ird von Yukihiro Yoshida, Hiroshi Kitagawa et al. in ihrem Forschungsartikel vorgestellt (e202213077). Die Funktionseinheit zeigte ein Protonen-Gleichrichtungsverhältnis von über 200, was dem hçchsten Wert unter den bekannten H + -OH À -Festkçrpergleichrichtern entspricht.