A Unique Structural Highly Compacted Binder-Free Silicon-Based Anode with High Electronic Conductivity for High-Performance Lithium-Ion Batteries

Herein, a unique structural Si-based anode with high electronic conductivity, high compact density, and with no traditional organic binder is put forward. By adding a few amounts of Sn to the Si anode material, followed by carbonization of the organic binder after the general anode preparation and subsequently hot pressing, Sn melts and squeezes during hot pressing, bonding strongly the Si particles, and an interlayer of Cu3Si/Cu3Sn is in situ formed at the interface of the Si-based active materials and the Cu current collector, resulting in a metallurgical bonding between them. The organic binder-derived carbon coats on the Si particles, coupling with the squeezed Sn and the Cu3Si/Cu3Sn interlayer, and a highly electron conductive skeleton is formed. The skeleton also offers a highly stable structural integrity of the electrode during cycling. With an optimization of the hot-pressing pressure, the Si-based anode shows superior cycling stability and rate performance. As the active materials are almost compacted to half of its initial thickness, the electrode has potential for high volumetric capacity. The fabrication method is new for Si-based anodes of high compact density. The work provides new insights into the development of advanced silicon-based anodes for lithium-ion batteries.

Automated summary

A novel structural Si-based anode with high compact density, stability, and superior performance during cycling is proposed in this study. The method involves adding a small amount of Sn to the Si anode material, carbonization of the organic binder, subsequent hot pressing, and the formation of a Cu3Si/Cu3Sn interlayer, leading to metallurgical bonding between the active materials and the current collector. The electrode shows potential for high volumetric capacity and offers new insights into advanced silicon-based anodes for lithium-ion batteries.