Boron–Based Electrolytes for Rechargeable Magnesium Batteries: Biography and Perspective

Abstract

Rechargeable magnesium batteries (RMBs) are a promising alternative in the post-lithium era for their high volumetric capacity, crustal abundance, and metallic safety. Electrolytes for RMBs have experienced a development process from the initial Grignard compound to today's diversified single magnesium salt. Among them, the boron-based electrolyte plays a significant connecting link between the preceding and the following. This review retrospectively combed the origin and development course of boron-magnesium electrolyte and focuses on the application of three representatives: borohydride, boron-center fluorinated alkoxylate, and closo-borane cluster. Fundamental understandings and typical concerns correlative with the MgÀ B electrolyte designs are highlighted and briefly discussed. Finally, future direction and possible proposals for practical MgÀ B electrolytes are put forward.[a] W.

Constructing Efficient Mg(CF3SO3)2 Electrolyte via Tailoring Solvation and Interface Chemistry for High‐Performance Rechargeable Magnesium Batteries

“…[9] Nevertheless, better accessibility through costcompetitive raw materials and simplified synthesis routes remains the key pursuits for these attractive WCA Mg salts. [10] Regarding the redox kinetics involved in the SEI, recent studies indicate that solvents play a decisive role. For instance, in both Mg[B(Ohfip 4 )] 2 and Mg[Al(Ohfip 4 )] 2 -based electrolytes, solutes exhibited more favorable electrochemical performance in diglyme (G2) solvent than that in glyme (DME) owing to its suitable chain length and ligand ability.…”

“…[ 9 ] Nevertheless, better accessibility through cost‐competitive raw materials and simplified synthesis routes remains the key pursuits for these attractive WCA Mg salts. [ 10 ]…”

Minireview on Metal–Chalcogenide Cathode Materials with Dual-Redox Centers for Magnesium-Metal-Anode-Based Batteries: Recent Progress and Future Directions

“…The development of an organic aluminate electrolyte derived from the reaction between Grignard reagent and AlCl 3 by Gregory et al enables reversible magnesium deposition, which promotes the rechargeability of magnesium batteries . The subsequent studies report a series of electrolytes such as magnesium hexamethyldisilazane (Mg­(HMDS)) based electrolytes, , magnesium aluminate chloride complex (MACC), , magnesium bis­(trifluoromethanesulfonyl)­imide [Mg­(TFSI) 2 ] based electrolytes, and boron-based Mg-ion electrolytes − for RMBs. The charge carrier in these electrolytes is the Mg–Cl complex cation or the Mg 2+ cation.…”

Long Cycle‐Life Ca Batteries with Poly(anthraquinonylsulfide) Cathodes and Ca−Sn Alloy Anodes

“…One major issue that hinders the development of Ca batteries is the incompatibility between the metal anode and non-aqueous electrolyte, similar as magnesium batteries. [3] Metallic Ca anode readily reacts with conventional aprotic solvents, forming a surface passivating film, [4] which allows the transport of Ca 2 + only at elevated temperature. [5] Calcium borohydride in tetrahydrofuran [Ca(BH 4 ) 2 /THF] is the first electrolyte enabling reversible Ca plating/stripping at room temperature, however, with anodic stability only up to 3 V vs. Ca.…”

“…One major issue that hinders the development of Ca batteries is the incompatibility between the metal anode and non‐aqueous electrolyte, similar as magnesium batteries [3] . Metallic Ca anode readily reacts with conventional aprotic solvents, forming a surface passivating film, [4] which allows the transport of Ca 2+ only at elevated temperature [5] .…”