Phase Separation Induced Binary Core-Shell Alloy Nanoparticles Embedded in Carbon Sheets for Magnesium Storage.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Magnesium-ion batteries (MIBs) offer potential for large-scale energy storage due to cost, capacity, and safety advantages.
• Reversible plating and stripping of magnesium metal anodes remain a significant challenge in MIB development due to electrolyte incompatibility.

Purpose of the Study:

• To design and fabricate a novel anode material for MIBs that overcomes the limitations of magnesium metal anodes.
• To investigate the electrochemical performance of binary Bi@Sn alloy nanoparticles embedded in carbon sheets (Bi@Sn-C) as a superior anode for MIBs.

Main Methods:

• Fabrication of Bi@Sn-C anode material through phase separation during annealing of bimetallic metal-organic frameworks (MOFs).
• Electrochemical testing of Bi@Sn-C electrodes in MIBs, including cycling stability and rate capability assessments.
• Optimization of electrochemical performance using a dual-salt electrolyte (LiCl-APC).

Main Results:

• Bi@Sn-C electrodes exhibited good cycling stability (214 mA h g⁻¹ at 100 mA g⁻¹ after 100 cycles) and rate capability (200 mA h g⁻¹ at 500 mA g⁻¹).
• Performance was further enhanced with the LiCl-APC electrolyte, achieving 308 mA h g⁻¹ at 100 mA g⁻¹ after 100 cycles and 238 mA h g⁻¹ at 500 mA g⁻¹.
• The nanostructure design and multi-element coordination of Bi@Sn-C improved structural stability and Mg²⁺ diffusion kinetics.

Conclusions:

• The developed Bi@Sn-C anode material demonstrates significant potential for efficient magnesium-ion storage.
• This strategy of using alloy nanoparticles embedded in carbon offers a promising pathway for designing advanced anode materials for MIBs.