Roll to roll manufacturing of fast charging, mechanically robust 0D/2D nanolayered Si-graphene anode with well-interfaced and defect engineered structures

Silicon/graphene composite is a promising material for Li-ion battery anodes towards high energy/power densities and reliable performances. Tuning the nanostructure in silicon/graphene composite can lead to many desired properties, such as high capacity, high rate performance and good cycle stability. However, the silicon/ graphene products of many existing approaches have many problems that are not fully resolved, including poor nanoscale uniformity, low mechanical strength, loose contacts and interfaces, low volumetric density and poor permeability of ions or electrolyte. These issues would cause the silicon/graphene anodes fail to deliver its best electrochemical performance. In this work, we report a layer-by-layer coated nanocomposite anode with well-integrated nanostructures, fabricated by a scalable laser shock assisted roll to roll deposition process. The nanocomposite anode consists of silicon nanoparticles (SiNPs) and reduced graphene oxide (RGO) sheets. The alternating SiNP and RGO nanolayers are compactly bonded with fine interfaces and wrapping effects after laser shock compression, resulting in higher mechanical strength of the overall electrode, without any binder addition. Moreover, highly dense nanoscale pores are found on the graphene sheets after laser shock compression and annealing, which help the infiltration of electrolyte and thus provides the extract channels for Li diffusion. The Si/ RGO composite anode can deliver a high specific capacity of 1956 mAh/g at a high cyclic rate of 15 A/g and retain 71.3% of the initial capacity after 1000 cycles. This work provides a general methodology to fabricate layered 0D/2D nanostructures with well-interfaced and defect-engineered nanostructures for many applications in electro-optics, molecule sensing, and energy storage.