A Unique Structural Highly Compacted Binder‐Free Silicon‐Based Anode with High Electronic Conductivity for High‐Performance Lithium‐Ion Batteries
Zhe Dong, Wubin Du, Haitao Gu, Yingying Long, Chenyang Zhang, Gairong Chen, Zhenhe Feng, Wenping Sun, Yinzhu Jiang, Yongfeng Liu, Yaxiong Yang, Jiantuo Gan, Mingxia Gao, Hongge Pan
Abstract
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 Cu 3 Si/Cu 3 Sn 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 Cu 3 Si/Cu 3 Sn 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.