Bionic Capsule Lithium-Ion Battery Anodes for Efficiently Inhibiting Volume Expansion.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Magnetite (Fe3O4) is a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity and abundance.
• However, Fe3O4 suffers from significant volume changes during lithiation, leading to poor cycle stability and rate performance.
• Addressing this volume expansion is crucial for practical LIB applications.

Purpose of the Study:

• To design and synthesize novel Fe3O4@PMMA multi-core capsules as anode materials for LIBs.
• To investigate the electrochemical performance and cycle stability of these bionic capsules.
• To propose a new evaluation method for assessing real-time battery capacity repair.

Main Methods:

• Microemulsion polymerization was employed to create Fe3O4@PMMA multi-core capsules.
• Electrochemical testing, including cyclic voltammetry and galvanostatic charge-discharge cycling, was performed.
• Pouch cells were assembled using LiNi0.8Co0.1Mn0.1O2 cathodes and Fe3O4@PMMA anodes for comprehensive evaluation.

Main Results:

• The Fe3O4@PMMA anode demonstrated a high reversible specific capacity of 858.0 mAh g⁻¹ at 0.1 C after 300 cycles.
• Excellent cycle stability was observed, with a capacity of 450.99 mAh g⁻¹ at 0.5 C after 450 cycles.
• LiNi0.8Co0.1Mn0.1O2/Fe3O4@PMMA pouch cells maintained 95.5% capacity after 450 cycles, with a remarkable 93.4% capacity repair rate.

Conclusions:

• Fe3O4@PMMA bionic capsules effectively mitigate volume expansion issues in magnetite anodes.
• The developed anode material exhibits superior electrochemical performance, including high capacity and excellent cycle stability.
• This innovative bionic capsule design offers a promising solution for advancing Fe3O4 anode applications in industrial LIBs.