A Metal–Organic Framework Thin Film for Selective Mg²⁺ Transport

Abstract

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 Ω cm2, with the normalized room‐temperature ionic conductivity of ca. 3.17×10−6 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.

Recent Development of Mg Ion Solid Electrolyte

“…Instead of pressed pellets, Luo, Tsung and Wang synthesized a Mg-MOF-74 thin film as the Mg ion conductor to eliminate interparticle gaps that were inevitable for pressed pellets and enabled studies on the inherent ionic conductivity of MOFs (Luo et al, 2019). It showed the ionic conductivity of 3.17 × 10 −6 S cm −1 at the room temperature, which was in consistent with the previous report by Aubrey.…”

Coupled Electrical Conduction in Coordination Polymers: From Electrons/Ions to Mixed Charge Carriers

“…Li‐ion conductivity of the sample was enhanced from 1.2×10 −5 S cm −1 to 3.1×10 −4 S cm −1 . Similar strategy could be extended for Mg‐ion conduction . By dipping Mg 2 (dobdc) and its extended analogue Mg 2 (dobpdc) (dobpdc 4− =4,4′‐dioxidobiphenyl‐3,3′‐dicarboxylate) in magnesium salt solution, the Mg 2+ ion conductivity reached 2.5×10 −4 S cm −1 .…”

Weak Coordination Bond of Chloromethane: A Unique Way to Activate Metal Node Within an Unstable Metal–Organic Framework DUT‐34

“…Metal–organic frameworks (MOFs), which are assembled by the continuous link of coordination bonds between inorganic metal ions (or metal‐oxo clusters) and polydentate organic ligands, are a highly crystalline subset of these fascinating porous materials. With their permanent porosity, exceptionally high internal surface area, wide chemical variety, and tunable topology, MOFs have been examined for their potential in applications such as gas uptake, 1–8 molecular separation, 1,2,9–16 drug delivery, 1,17–20 sensing, 21–25 ion transport, 1,2,26–31 electronic conduction, 1,32–38 among others 39–44 …”