Solid Solution of Bi and Sb for Robust Lithium Storage Enabled by Consecutive Alloying Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Alloying materials offer high theoretical capacity for lithium-ion batteries (LIBs).
• Volume expansion and pulverization limit the cycling performance of traditional alloying electrodes.
• Controlling reaction pathways is crucial for stable alloying electrode performance.

Purpose of the Study:

• To develop a novel electrode material for LIBs that overcomes the limitations of volume expansion and pulverization.
• To investigate the mechanism of consecutive alloying reactions in a carbon-encapsulated Bi-Sb system.
• To demonstrate the enhanced electrochemical performance of the developed electrode for LIBs.

Main Methods:

• Synthesis of carbon-encapsulated Bi_0.5 Sb_0.5 solid solution.
• Electrochemical characterization of the electrode material in LIBs.
• Analysis of the structural evolution and reaction mechanism during cycling.

Main Results:

• The carbon encapsulation facilitates consecutive alloying reactions between Bi, Sb, and Li, forming a Sb-rich shell and Bi-rich core structure.
• The Bi_0.5 Sb_0.5 @carbon electrode exhibits a high reversible capacity of 489.4 mAh g^-1 after 2000 cycles at 1 A g^-1.
• Controlled alloying reactions prevent severe volume changes and pulverization, leading to robust cyclability and fast kinetics compared to bare Bi_0.5 Sb_0.5.

Conclusions:

• Carbon-encapsulated Bi_0.5 Sb_0.5 is a promising electrode material for high-capacity and long-life LIBs.
• The strategy of controlled consecutive alloying reactions via carbon encapsulation effectively mitigates volume expansion issues.
• This approach offers a pathway for developing advanced alloy electrodes for rechargeable batteries with potential industrial applications.