Unveiling the Roles of Formation Process in Improving Cycling Performance of Magnesium Stannide Composite Anode for Magnesium‐Ion Batteries

Abstract

The combination of Mg2+‐insertion type anodes with various Mg‐free cathode counterparts and electrolytes enables Mg‐ion batteries. Microsized magnesium stannide (Mg2Sn) active material for a potential Mg2+‐insertion anode has shown extremely low capacity and low Coulombic efficiency in the early cycles, due to not yet a full participation of active material and an irreversible capacity loss by anode–electrolyte interfacial reactions. An activation process, i.e., formation cycle, is necessary to mitigate those issues and to improve the cycling performance. Herein, the application of formation process to the Mg2Sn composite anode that includes graphite as an electrochemically inactive but electronically conductive component, the condition optimization of formation process, and the systematic studies of the effects of formation process on the cycling performance and anode–electrolyte interfacial reactions are reported. A basic understanding of the early cycling behavior and interfacial phenomena of Mg2Sn anode is provided, which gives insight into improvement of performance of alloy anodes in Mg‐ion batteries.

The Effect of Sn Addition on Zn-Al-Mg Alloy; Part II: Corrosion Behaviour

“…In a more detailed image (Figure 8b) it can be seen that α(Al) and MgxZny particles were corroded. Mg2Sn particles were subject to the process of dealloying [28][29][30][31], leaving thus pure metallic Sn particles behind. The depth of IG corrosion is significantly lower for the annealed samples with maximums reaching only about 70 µm even after 1000 h of NSST.…”

“…In a more detailed image ( Figure 8 b) it can be seen that α(Al) and Mg x Zn y particles were corroded. Mg 2 Sn particles were subject to the process of dealloying [ 28 , 29 , 30 , 31 ], leaving thus pure metallic Sn particles behind.…”

Beyond Lithium-Based Batteries

“…The main eleven categories for the cathode materials are metal selenides [24,74], metal oxides [75][76][77][78][79][80], carbon [81][82][83][84], metal sulfides [85][86][87], Prussian blue [88], Mg-OMS-1 [89], polyoxometalate-(poly)pyrrole [90], MXene [91], metal phosphates [92,93] and magnesium octahedral molecular sieves [94]. Research in anode material is mainly focused on alloys [95][96][97][98]. We will use a selection of these material types to explain magnesium storage mechanisms.…”

“…This reaction forms a passivating layer at its surface and preventing the reversible plating and stripping of Mg. One can avoid this layer formation by using magnesium-metal alloys. The materials explored for this application are bismuth nanocrystals, a magnesium/tin alloy [96,98], bismuth/tin alloy [95] and a biphase bismuth-tin film [97]. Out of these materials, only the bismuth nanocrystals have been tested as anode in a full battery cell.…”

“…The other alloy materials were tested for their magnesium storage/release capabilities [95][96][97][98]. The materials are tested with magnesium as a counter/reference electrode, effectively making them the cathode in these systems.…”