A Study on the Nanostructural Evolution of Bi/C Anode Materials during Their First Charge/Discharge Processes

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Bismuth-based materials are promising anode candidates for lithium-ion batteries due to their high capacity and eco-friendliness.
• However, significant volume changes during cycling hinder their practical application and complicate understanding of their lithium storage mechanisms.

Purpose of the Study:

• To synthesize and characterize Bi/C nanocomposites as anode materials for lithium-ion batteries.
• To investigate the structural evolution and reaction mechanisms of Bi/C anodes during the initial charge-discharge cycle using advanced in situ techniques.

Main Methods:

• Bi/C nanocomposites were prepared via calcination of a bismuth-based metal-organic framework (MOF) precursor.
• In situ synchrotron radiation small-angle X-ray scattering (SAXS) was employed to monitor structural changes during the first lithiation/delithiation cycle.

Main Results:

• The synthesized Bi/C nanocomposite exhibited a high specific capacity of 931.6 mAh g⁻¹ after 100 cycles at 100 mA g⁻¹ with good rate performance.
• In situ SAXS analysis identified mesopores, interspaces, and Bi nanoparticles as key structural components influencing performance.
• Distinct nanostructure evolution pathways were observed for different types of Bi nanoparticles during lithiation.

Conclusions:

• The Bi/C nanocomposite demonstrates excellent electrochemical performance as a lithium-ion battery anode.
• Understanding the nanostructure evolution via in situ SAXS provides crucial insights into the complex reaction mechanisms of Bi-based anodes.
• This study facilitates further development of high-performance bismuth-based anode materials.