A Metal-Organic Framework Thin Film for Selective Mg 2+ Transport.

The incompatibility between the anode and the cathode chemistry limits the used of Mg as an anode. This issue may be addressed by separating the anolyte and the catholyte with a membrane that only allows for Mg2+ transport. Mg-MOF-74 thin films were used as the separator for this purpose. It was shown to meet the needs of low-resistance, selective Mg2+ transport. The uniform MOF thin films supported on Au substrate with thicknesses down to ca. 202 nm showed an intrinsic resistance as low as 6.4 omega cm(2), with the normalized room-temperature ionic conductivity of ca. 3.17x10(-6) S cm(-1). When synthesized directly onto a porous anodized aluminum oxide (AAO) support, the resulting films were used as a standalone membrane to permit stable, low-overpotential Mg striping and plating for over 100 cycles at a current density of 0.05 mA cm(-2). The film was effective in blocking solvent molecules and counterions from crossing over for extended period of time.