Improved Cyclability of Silicon/Porous-Carbon Composite with Ag Nanoparticles for Lithium-Ion Battery Anodes

A Silicon/Porous-Carbon (Si/Porous-C) composite with Ag nanoparticles was prepared by the co-assembly of polyvinylidene fluoride (PVdF), nano-SiO2 (~20 nm), AgNO3 and Si nanoparticles (~ 50 nm) followed by a carbonizing process and subsequent removal of SiO2 template. The Si/Porous-C and Ag/Si/Porous-C composite were characterized by scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD). Ag nanoparticles remained even after heat treatment at high temperature and hydrofluoric acid etching. The Ag/Si/Porous-C composite electrode exhibited good electrochemical performances with a reversible capacity of 1,470 mAh/g as an anode material in lithium-ion cells, showing a stable capacity of 1,150 mAh/g after 100 cycles at a rate of 500 mA/g per hour. Cycling performances of the Si/Porous-C and Ag/Si/Porous-C composite electrodes were determined at various rates as shown in figure. The Ag/Si/Porous-C composite electrode showed better rate capability and recovery as the rates decreased, while the capacity of the Si/Porous-C composite electrode faded drastically as the rates increased. Figure 1