Accurate ion/solvent separation via pore‐size‐customized MOF membrane for hydrogen evolution‐free aqueous zinc batteries

Abstract The practical application of aqueous zinc (Zn) batteries is largely limited by the detrimental hydrogen evolution reaction (HER) on the Zn metal surface. Herein, an effective ion/solvent separation strategy is proposed to construct a uniform and seamless MOF membrane on a 3D Zn foam surface, by which the selective Zn 2+ transport and accurate H 2 O molecules separation from the MOF channels can be realized, thereby obtaining a HER‐free Zn anode. Specifically, by screening 10 Zn‐MOF candidates through theoretical calculations, a pore‐size‐customized ZIF‐8 was selected for the accurate Zn 2+ /H 2 O separation because of its superior adsorption characteristics and nominal aperture pore size. Then, a series of in situ characterizations and experiments demonstrate that negligible amounts of H 2 gas are observed from the MOF@Zn foam anode. Consequently, the ion/solvent separation effect is verified by HER‐free MOF@Zn foam‐based coin full cells delivering 78.1% capacity after 500 cycles and large‐scale pouch cells with expected performance.