In Situ Interfacial Passivation in Aqueous Electrolyte for Mg‐Air Batteries with High Anode Utilization and Specific Capacity

Abstract

Mg‐air batteries are a promising new generation of batteries because they can operate in neutral electrolytes that are safe and nontoxic. However, the high corrosion and low utilization of Mg anodes in Mg‐air batteries result in low specific capacity and severe self‐discharge. In this study, an Mg(OTf)2‐based aqueous electrolyte is developed, which addresses these issues by reducing the contact of the Mg anode with water molecules from the hydrophobic −CF3 groups and forming an MgF2 protective layer. The assembled Mg‐air batteries exhibit specific capacities of up to 1920 mAh g−1Mg (87.32 % utilization based on the Mg anode). In addition, the resting time of the corresponding Mg‐air batteries was 123 times longer than that of Mg‐air batteries with pure NaCl electrolytes under the same conditions.

An ultrahigh energy density Mg–air battery with organic acid–solid anolyte biphasic electrolytes

“…3f). 2–5,7,37,50 In comparison, battery B only reaches mediocre anode energy densities of 350.6 W h kg −1 and 1112.9 W h kg −1 at the same current densities.…”