Alloy Alleviating Galvanic Corrosion Enables Uniform Mg Deposition with Long Cycle Life

The magnesium anode is one of the most promising metal anode candidates due to the great safety ascribed to it because it is free of sharp dendrites under general working conditions. However, a pure magnesium metal anode suffers from uneven plating, which could lead to voltage fluctuation and increasing polarization during cycling, affecting its cycle life. Here, Ce whose standard electrode potential (−2.34 V vs SHE) is extremely close to that of Mg (−2.37 V vs SHE) is introduced into magnesium as alloying element to form a magnesiophilic Mg-xCe alloy, alleviating the galvanic corrosion effect, preferentially adsorbing Mg2+ ions and effectively facilitating nucleation of Mg on the Mg-xCe alloy electrode surface, enhancing the cycle performance. Particularly, the optimized Mg-0.5Ce alloy displays 1932 h of Mg stripping/plating cycles. Elements with magnesiophilic ability and electrode potential close to magnesium can open a new design strategy for improving the electrochemical performance of the magnesium anode.