Microstructure modulation improving the stability performance of a Bi anode for lithium-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Metallic bismuth (Bi) offers high theoretical capacity for battery anodes but suffers from significant volume changes during cycling, leading to performance degradation.
• Developing strategies to mitigate bismuth's volume expansion is crucial for improving anode material stability and cycle life.

Purpose of the Study:

• To design and synthesize a stable bismuth-based anode material with enhanced electrochemical performance.
• To suppress the volume expansion of bismuth during charge-discharge cycles using a novel structural approach.

Main Methods:

• Utilized a bismuth-metal-organic-framework (Bi-MOF) as a precursor.
• Employed an organic polymerization coating process followed by calcination to create a double-carbon-coated lamellar structure (Bi/C@C_Ppy).
• Conducted electrochemical performance testing, including long-term cycling stability, and utilized in situ X-ray diffraction (XRD) to study the Li⁺ storage mechanism.

Main Results:

• The Bi/C@C_Ppy anode material exhibited excellent capacity retention, maintaining 526.4 mA h g^-1 after 100 cycles at 0.1 A g^-1 and 255.6 mA h g^-1 after 900 cycles at 0.5 A g^-1.
• The double-carbon coating effectively inhibited Bi particle agglomeration and mitigated volume changes.
• A full cell utilizing Bi/C@C_Ppy as the anode achieved a capacity of 104.3 mA h g^-1 after 100 cycles at 0.05 A g^-1.

Conclusions:

• The developed Bi/C@C_Ppy material demonstrates significant potential as a high-performance anode for rechargeable batteries.
• The strategy of using Bi-MOF precursors and double-carbon coating provides a viable route for designing stable alloy anode materials.
• This work offers valuable insights into structural engineering for advanced battery electrode materials.