Cross-linking γ-Polyglutamic Acid as a Multifunctional Binder for High-Performance SiO Anode in Lithium-Ion...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon oxide (SiO) is a promising high-capacity anode material for lithium-ion batteries.
• Significant volume expansion during cycling limits the practical application of SiO anodes.
• Binder development is a key strategy to improve the electrochemical performance of SiO anodes.

Purpose of the Study:

• To fabricate a multifunctional binder (T-PGA) for SiO anodes by cross-linking γ-polyglutamic acid (PGA) and tannic acid (TA).
• To investigate the effects of the T-PGA binder on buffering volume changes, facilitating Li+ diffusion, and constructing stable SEI layers for SiO anodes.

Main Methods:

• Fabrication of a multifunctional binder (T-PGA) through cross-linking of γ-polyglutamic acid (PGA) and tannic acid (TA).
• Electrochemical testing of SiO anodes with the T-PGA binder, including cycling performance and capacity retention.
• Assembly and testing of a full cell using the T-PGA binder-modified SiO anode and a LiNi0.5Co0.2Mn0.3O2 cathode.

Main Results:

• The T-PGA binder effectively buffered the volume changes of SiO anodes during cycling.
• The SiO anode with T-PGA maintained a reversible capacity of 973.0 mAh g⁻¹ after 500 cycles at 500 mA g⁻¹.
• The full cell demonstrated a reversible capacity of 133 mAh g⁻¹ (73.2% retention) after 100 cycles.

Conclusions:

• The developed T-PGA binder significantly enhances the electrochemical performance and cycling stability of SiO anodes.
• This multifunctional binder offers a promising solution for practical, high-capacity lithium-ion batteries utilizing SiO anodes.
• The study provides valuable insights into the design of advanced binders for next-generation energy storage systems.