Reversible Magnesium Metal Cycling in Additive-Free Simple Salt Electrolytes Enabled by Spontaneous Chemical Activation

Abstract

Rechargeable magnesium (Mg) batteries can offer higher volumetric energy densities and be safer than their conventional counterparts, lithium-ion batteries. However, their practical implementation is impeded due to the passivation of the Mg metal anode or the severe corrosion of the cell parts in conventional electrolyte systems. Here, we present a chemical activation strategy to facilitate the Mg deposition/stripping process in additive-free simple salt electrolytes. By exploiting the simple immersion-triggered spontaneous chemical reaction between reactive organic halides and Mg metal, the activated Mg anode exhibited an overpotential below 0.2 V and a Coulombic efficiency as high as 99.5% in a Mg(TFSI)2 electrolyte. Comprehensive analyses reveal simultaneous evolution of morphology and interphasial chemistry during the activation process, through which stable Mg cycling over 990 cycles was attained. Our activation strategy enabled the efficient cycling of Mg full-cell candidates using commercially available electrolytes, thereby offering possibilities of building practical Mg batteries.

Micro-selection and Macro-orientation Strategy Enables High-Areal-Capacity Magnesium Metal Anode

“…It is worth noting that Mg experienced rapid short-circuiting during successive rate tests. To the best of our knowledge, combining the above electrochemical properties, this cycling durability at high areal capacity in this work is at the forefront of various Mg anodes previously reported ,− (Figure S16).…”

Asymmetric SO3CF3−‐Grafted Boron‐Center Anion Enables Boron‐Containing Interphase for High‐Performance Rechargeable Mg Batteries

“…Recently, researchers gradually focused on highvoltage, high-ionic-conductivity and simple Magnesium Bis(trifluoromethanesulfonyl)imide (Mg(TFSI) 2 ) [29][30][31][32][33] and Magnesium trifluoromethanesulfonate (Mg(OTf) 2 ) [34,35] /ether electrolytes. Among them, Mg(OTf) 2 possesses a lower cost relative to Mg(TFSI) 2 , and OTf − anion has better anodic stability than TFSI − , which is a promising salt for high-voltage electrolyte systems.…”

Binary Mg‐1 at%Gd alloy anode for high‐performance rechargeable magnesium batteries

“…The current strategies for optimizing the electrochemical performance of Mg anode primarily includes the electrolyte modification, [14][15][16] designing artificial solid-electrolyte-interphase (SEI), [17][18][19][20] constructing three-dimensional hosts, [21,22] designing the magnesiophilic sites, [23,24] and so forth. [25] These works could effectively inhibit the surface passivation between Mg and electrolytes and improving the uniformity/kinetics of Mg plating/stripping, thus enhancing the cycling stability and rate performance.…”