An Adhesion-Toughness-Balanced Binder for Stabilizing Silicon-Based Anodes in Pouch Cells.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• High-capacity silicon anodes suffer from severe volume expansion during cycling.
• Existing binders lack the necessary combination of adhesion and toughness to accommodate silicon's volume changes.
• A new binder design is needed to enhance battery stability and longevity.

Purpose of the Study:

• To develop a novel binder with balanced adhesion and toughness for silicon-based anodes.
• To investigate the performance of this binder in high-energy density batteries.
• To demonstrate the binder's applicability in both pouch cells and all-solid-state lithium-ion batteries.

Main Methods:

• Fabrication of a linear-particulate composite network binder using highly elastic emulsion particles within a robust 3D framework.
• Characterization of the binder's mechanical properties (adhesion and toughness).
• Electrochemical testing of silicon-based anodes utilizing the developed binder in pouch cells and all-solid-state lithium-ion batteries.

Main Results:

• The composite binder effectively mitigates stress from silicon volume expansion.
• Pouch cells with the binder retained 82.5% capacity after 500 cycles at 1 C.
• All-solid-state lithium-ion batteries with silicon anodes demonstrated 73.6% capacity retention over 1800 cycles at 1.5 C.

Conclusions:

• The developed composite binder offers a synergistic balance of adhesion and toughness.
• This binder significantly enhances the cycle life and performance of high-capacity silicon anodes.
• The binder shows broad applicability for next-generation high-performance batteries, including silicon-based pouch cells and ASSLIBs.