Phase-Structure\nModulated Self-Supporting Indium–Bismuth\nAlloy Films as Anodes for Advanced Magnesium Ion Batteries

Alloy-type anodes used in magnesium ion batteries (MIBs)\nhave garnered\nsignificant attention in light of their substantial theoretical specific\ncapacities and possible matchability with conventional electrolytes.\nHowever, the major challenges for alloy-type anodes are the sluggish\ntransport kinetics as well as severe volume variations during the\ndischarge/charge processes. Herein, we present a strategy for phase-structure\nmodulation to fabricate a self-supporting In–Bi film through\nstraightforward magnetron sputtering. In comparison to the single-phase\nIn and Bi electrodes, the biphase InBi/Bi electrode displays markedly\nenhanced rate and cycling performance, with the discharge capacities\nof 303.1/292.6 mAh g<sup>–1</sup> after 550/500 cycles at 200/2000\nmA g<sup>–1</sup>, respectively. The exceptional Mg storage\ncapability of the sputtered InBi/Bi electrode could be ascribed to\nthe favorable two-phase configuration and increased phase boundaries,\neffectively accommodating volume expansion and accelerating Mg<sup>2+</sup> ion transport. More importantly, the (de)magnesiation mechanism\nof InBi/Bi for MIBs was elucidated through operando X-ray diffraction.