Self-supporting Mg–Sn alloy anode for high-energy Li-ion batteries

Abstract

Due to advantages such as low reaction potential, high gravimetric and volumetric capacity, and minimal structural changes during interaction with lithium, the research on Mg anodes in Li-ion batteries has garnered significant attention. However, the slow diffusion kinetics of Li in Mg limits its further advancement. In this study, we designed an ultrathin, flexible, and self-supporting Mg–Sn alloy anode featuring an interleaved two-phase distribution. The electrode was fabricated through a simple one-step magnetron sputtering method, which circumvents the need for complex procedures like slurry preparation and coating. Both theoretical calculations and experimental results indicate that the introduction of a second phase(Mg₂Sn phase) significantly enhances the interaction between Mg and Li, thereby unlocking the lithium storage capabilities of Mg. The developed Mg–Sn alloy electrode demonstrates a charge specific capacity of 1618 mAh g⁻¹ at 50 mA g⁻² and maintains a capacity of 421 mAh g⁻¹ after 50 cycles.