Tailoring Ion-Conducting Interphases on Magnesium Metals for High-Efficiency Rechargeable Magnesium Metal Batteries

Abstract

Magnesium (Mg) rechargeable batteries are one of the promising highenergy post-lithium battery chemistries exploiting the multivalent charge carrier. However, the use of magnesium metal has been challenging due to the formation of the ion-blocking passivation layer on magnesium metal in most organic electrolytes. Herein, we propose a new strategy to transform the passivating film into a Mg 2+conductive interphase via simple chemisorption of sulfur dioxide molecules on magnesium metal. The facile chemical tuning converts the magnesium oxide-based passivation layer into a magnesium sulfate-like phase, which greatly enhances the chargetransfer capability of multivalent Mg 2+ ions. The reduced surface resistance of the magnesium metal results in efficient magnesium stripping/deposition reactions even under conventional ether-based electrolytes. Theoretical calculations support that the facile ionic conduction is attributed to the relatively low Mg 2+ dissociation and migration energies in the tailored interphases. Furthermore, we elucidate the degradation mechanism of magnesium electrodes by combining various experimental analyses with computational calculations.

Defect‐Free Metal–Organic Framework Membrane for Precise Ion/Solvent Separation toward Highly Stable Magnesium Metal Anode

“…[ 1 ] However, an ionic passive interfacial layer as a result of the reduction of thermodynamically unstable solvated species usually hinders Mg 0 /Mg 2+ reaction in conventional electrolytes. [ 2 ] A solution is to construct a high Mg 2+ ‐conductive interphase that allows the reversible Mg 2+ plating/stripping, which has recently been achieved by polymeric coating, [ 3 ] alloying, [ 4 ] inorganic halogen compounds modification [ 5 ] and gas‐chemisorption, [ 6 ] etc. Tracing back to the origin of this passive layer, another solution is to decrease the strong electrostatic interactions between Mg 2+ and solvent to prevent it from reduction.…”

A Bismuth-Based Protective Layer for Magnesium Metal Anode in Noncorrosive Electrolytes

“…Nevertheless, among these strategies for in situ generation of the interphase during the electrochemical process, the uncontrolled electrolyte reduction of Mg salts or electrolyte additives are not conducive to precisely adjust the composition, thickness, and mechanical and chemical properties of the as-formed SEI. Therefore, directly and simply modifying the Mg metal surface with well-designed artificial coating materials prior to battery assembly may be a more promising and practical approach. − One of the most noteworthy is that Ban et al designed a electronic-insulating and Mg 2+ -conducting artificial interphase on the Mg metal surface, which accomplished extremely reversible Mg plating/stripping behavior in Mg electrolytes with high oxidation stability . However, the additional procedures of these artificial coating strategies are mostly too complicated for large-scale applications.…”

Rational Design Strategy of Novel Energy Storage Systems: Toward High‐Performance Rechargeable Magnesium Batteries

“…[ 32 ] In the following decades, increasing related works have emerged year by year. [ 26,33–43 ] However, the development of RMBs is still in the primary stage, and the main challenges are as follows. First, conventional polar aprotic solvents and salt anions are reactive with Mg metal, which leads to insulating passivation film formation and thus blocks reversible Mg 2+ transportation at room temperature.…”

“…First, conventional polar aprotic solvents and salt anions are reactive with Mg metal, which leads to insulating passivation film formation and thus blocks reversible Mg 2+ transportation at room temperature. [ 26,38,44 ] Second, suitable cathode materials with high reversible capacity and fast kinetics of Mg 2+ are rare due to the strong electrostatic interaction of Mg 2+ with the inorganic host. [ 45–48 ] Therefore, exploring appropriate electrode materials and compatible electrolytes are the key strategies to achieve high‐performance RMBs.…”