Bio-inspired rigid helical network for silicon anode binders enabled by metal-ion-mediated conformation regulation

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Silicon anodes in lithium-ion batteries suffer from volume expansion, leading to electrode degradation and capacity fade.
• Polysaccharide binders offer crosslinking but their potential for precise polymer chain conformation control is underexplored.

Purpose of the Study:

• To investigate metal-ion-mediated conformational changes in xanthan gum (XG) for enhanced binder performance in silicon anodes.
• To develop a scalable strategy for improving the mechanical properties of binders for next-generation batteries.

Main Methods:

• Bio-inspired strategy using metal ions (CaCl₂) to induce conformational contraction of XG chains.
• Low-temperature pyrolysis to solidify the engineered polymer network.
• Computational simulations (DFT, MD) and multiscale characterization to optimize binder formulation.

Main Results:

• Xanthan gum chains transformed from helical to rigid rod-like structures, forming a dense 3D network.
• Optimal 1% CaCl₂/XG ratio achieved superior mechanical confinement, suppressing silicon volume expansion.
• The optimized binder electrode exhibited a specific capacity of 1885.8 mAh g⁻¹ after 300 cycles, showing remarkable stability.

Conclusions:

• Regulating molecular chain conformation is a versatile route to enhance binder performance in silicon anodes.
• The developed bio-inspired binder significantly improves cycling stability and capacity retention in lithium-ion batteries.
• This approach holds potential for other polysaccharide-based functional materials.