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

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.