Hierarchical Bi@Ni Foam as a Self-Supporting Anode for Superior Magnesium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Rechargeable magnesium-ion batteries (MIBs) offer safe and cost-effective energy storage.
• Mg metal anodes face electrolyte incompatibility issues.
• Bismuth (Bi) anodes have high capacity but suffer from volume variation.

Purpose of the Study:

• To develop a stable and high-performance anode for MIBs.
• To address the volume expansion challenge in Bi anodes.
• To improve the kinetics and cycling stability of MIB anodes.

Main Methods:

• Fabrication of a binder-free, self-supporting Bi@Ni foam anode using a spontaneous displacement reaction.
• Utilizing a 3D interconnected Ni foam architecture.
• Density Functional Theory (DFT) calculations to study Mg2+ adsorption.

Main Results:

• The Bi@Ni foam anode effectively accommodates volume changes, preventing pulverization.
• Ni substrate enhances Mg2+ adsorption energy and reaction kinetics.
• Achieved a reversible capacity of 202.4 mAh g-1 after 200 cycles at 0.25C.
• A full cell demonstrated a discharge capacity of 61.2 mAh g-1 after 23 cycles at 0.2C.

Conclusions:

• The Bi@Ni foam anode presents a scalable strategy for high-performance multivalent-ion battery anodes.
• This approach overcomes key limitations of Mg metal and Bi anodes.
• Offers a promising direction for next-generation energy storage solutions.