Binder-Free, Flexible, and Self-Standing Non-Woven Fabric Anodes Based on Graphene/Si Hybrid Fibers for High-Performance Li-Ion Batteries.

High-capacity silicon (Si) is recognized as a potential anode material for high-performance lithium-ion batteries (LIBs). Unfortunately, large volume expansion during discharge/charge processes hinders its areal capacity. In this work, we design a flexible graphene-fiber-fabric (GFF)-based three-dimensional conductive network to form a binder-free and self-standing Si anode for high-performance LIBs. The Si particles are strongly wrapped in graphene fibers. The substantial void spaces caused by the wrinkled graphene in fibers enable effective accommodation of the volume change of Si during lithiation/delithiation processes. The GFF/Si-37.5% electrode exhibits an excellent cyclability with a specific capacity of 920 mA h g-1 at a current density of 0.4 mA cm-2 after 100 cycles. Furthermore, the GFF/Si-29.1% electrode exhibits an excellent reversible capacity of 580 mA h g-1 at a current density of 0.4 mA cm-2 after 400 cycles. The capacity retention of the GFF/Si-29.1% electrode is up to 96.5%. More importantly, the GFF/Si-37.5% electrode with a mass loading of 13.75 mg cm-2 achieves a high areal capacity of 14.3 mA h cm-2, which outperforms the reported self-standing Si anode. This work provides opportunities for realizing a binder-free, flexible, and self-standing Si anode for high-energy LIBs.