Facilitated magnesium atom adsorption and surface diffusion kinetics via artificial bismuth-based interphases

Area of Science:

• Materials Science
• Electrochemistry
• Inorganic Chemistry

Background:

• Magnesium batteries are a promising alternative to lithium-ion batteries due to magnesium's high volumetric capacity and abundance.
• Developing stable and efficient interfaces is crucial for overcoming challenges in magnesium battery technology, such as dendrite formation and sluggish kinetics.

Purpose of the Study:

• To engineer robust bismuth-based interphases for enhanced magnesium deposition and stripping.
• To investigate the role of these interphases in facilitating magnesium ion adsorption and migration.
• To quantify the reduction in electrochemical energy penalty during magnesium nucleation and growth.

Main Methods:

• Galvanic replacement reactions were employed to synthesize bismuth and bismuth oxide interphases.
• Electrochemical techniques were used to evaluate the performance of the interphases in a magnesium battery system.
• Surface characterization methods were utilized to analyze the composition and structure of the interphases.

Main Results:

• Robust bismuth-based interphases were successfully fabricated.
• The interphases demonstrated facilitated magnesium atom adsorption and distinct interfacial magnesium atom migration.
• A significant reduction in the electrochemical energy penalty was observed: 23 mV for nucleation and 69 mV for growth at 1.0 mA cm^-2.

Conclusions:

• Bismuth-based interphases effectively lower the energy barriers for magnesium deposition and stripping.
• The engineered interphases promote reversible magnesium plating/stripping, crucial for practical magnesium battery applications.
• This work offers a viable strategy for developing advanced interphases to enable high-performance magnesium batteries.