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Rechargeable magnesium batteries (RMBs) have the potentials in terms of high energy density, resource abundancy and safety beyond current lithium‐ion batteries. However, the bare Mg metal electrode is prone to be passivated by solvents, suffering from the extremely high overpotential and short life during cycling. Herein, a facile chloride‐free solution pretreatment method for Mg anode is developed to construct the fluoride‐rich artificial interphase. Driven by the strong‐Lewis‐acidity trifluoromethanesulfonate anion, the interphase consisting of magnesiophilic and fluoride‐rich components are constructed by the substitution reaction of Mg metal with antimony trifluoride. The formed porous Sb‐based skeletons can uniform the electric‐field distribution and Mg ions flux at anode side, inducing the self‐adapting dendrite‐free Mg deposition even under large current density. The generated alloyable metal fluoride enables to lower the desolvation energy barrier for Mg ions and sustainedly release metallic antimony to compensate for the potentially invalid magnesiophilic sites during cycling. Therefore the symmetric cells with modified Mg anodes achieve the excellent cycling over 2000 h at 1 mA cm−2 and under a high areal capacity of 5 mAh cm−2. The full cells with CuS cathodes exhibit a superior high voltage stability (2.6 V vs Mg/Mg2+) and high coulombic efficiency close to 100%. [ABSTRACT FROM AUTHOR]

Rechargeable magnesium batteries (RMBs) become a highly promising candidate for the large‐scale energy storage system by right of the high volumetric capacity, intrinsic safety and abundant resources of Mg anode. However, the uneven Mg stripping and large overpotential will cause a severe pitting perforation and the followed failure of Mg anode. Herein, we proposed a high‐performance binary Mg‐1 at% Gd alloy anode prepared by the melting and hot extrusion. The introduction of 1 at% Gd element can effectively reduce the Mg2+ diffusion energy barrier (0.34 eV) on alloy surface and induces the formation of a robust and low‐resistance electrolyte/anode interphase, thus enabling a uniform and fast Mg plating/stripping. As a result, the Mg‐1 at.% Gd anode displays a largely enhanced life of 220 h and a low overpotential of 213 mV at a high current density of 5.0 mA cm−2 with 2.5 mAh cm−2. Moreover, the assembled Mg‐1 at.% Gd//Mo6S8 full cell delivers a high rate performance (73.5 mAh g−1 at 5 C) and ultralong cycling stability of 8000 cycles at 5 C. This work brings new insights to design the new‐type and practical Mg alloy anodes for commercial RMBs. [ABSTRACT FROM AUTHOR]

In recent decades, rechargeable Mg batteries (RMBs) technologies have attracted much attention because the use of thin Mg foil anodes may enable development of high‐energy‐density batteries. One of the most critical challenges for RMBs is finding suitable electrolyte solutions that enable efficient and reversible Mg cells operation. Most RMB studies concentrate on the development of novel electrolyte systems, while only few studies have focused on the practical feasibility of using pure metallic Mg as the anode material. Pure Mg metal anodes have been demonstrated to be useful in studying the fundamentals of nonaqueous Mg electrochemistry. However, pure Mg metal may not be suitable for mass production of ultrathin foils (<100 microns) due to its limited ductility. The metals industry overcomes this problem by using ductile Mg alloys. Herein, the feasibility of processing ultrathin Mg anodes in electrochemical cells was demonstrated by using AZ31 Mg alloys (3 % Al; 1 % Zn). Thin‐film Mg AZ31 anodes presented reversible Mg dissolution and deposition behavior in complex ethereal Mg electrolytes solutions that was comparable to that of pure Mg foils. Moreover, it was demonstrated that secondary Mg battery prototypes comprising ultrathin AZ31 Mg alloy anodes (≈25 μm thick) and MgxMo6S8 Chevrel‐phase cathodes exhibited cycling performance equal to that of similar cells containing thicker pure Mg foil anodes. The possibility of using ultrathin processable Mg metal anodes is an important step in the realization of rechargeable Mg batteries. [ABSTRACT FROM AUTHOR]

There is an increasing demand for rechargeable batteries in high-performance energy storage systems. The current dominating Li-ion batteries are limited by price, resource availability, as well as their theoretical capacities. So that the community has started to explore alternative battery chemistries. As a promising multivalent battery type, rechargeable magnesium batteries (RMBs) have attracted increasing attention because of high safety, high volumetric energy density, and low cost thanks to abundant resource of Mg. However, the development of high-performance anodes is still hampered by formation of passivating layers on the Mg surface. Additionally, dendrites can also grow under certain conditions with pure Mg anodes, which requires further studies for reliable operation window and substitutes. Therefore, this review specifically aims to provide an overview on the often overlooked yet very important anode materials of RMBs, with the hope to inspire more attention and research efforts for the achievement of over-all better performance of future RMBs. [ABSTRACT FROM AUTHOR]

Keywords: batteries; electrochemistry; energy storage; Mg electrodes; rechargeable Mg batteries EN batteries electrochemistry energy storage Mg electrodes rechargeable Mg batteries 4611 4611 1 11/09/21 20211104 NES 211104 B The Cover Feature b shows the electrochemical performance of 25 m AZ31 alloy as anode, in a full magnesium cell with Chevrel phase as cathode, in 0.25 m APC as electrolyte. Batteries, electrochemistry, energy storage, Mg electrodes, rechargeable Mg batteries. [Extracted from the article]