Silicon nanoparticles grown on a reduced graphene oxide surface as high-performance anode materials for lithium-ion batteries†
The growth of silicon nanoparticles on a graphene surface without forming the unwanted silicon carbide (SiC) phase has been challenging. Herein, the critical issues surrounding silicon anode materials for lithium-ion batteries, such as electrode pulverization, unstable solid electrolyte interphase and low electrical conductivity, have been addressed by growing silicon nanoparticles smaller than 10 nm, covalently bonded to a reduced graphene oxide (rGO) surface. The successful growth of SiC-free silicon nanoparticles covalently attached to the rGO surface was confirmed by using various spectroscopic and microscopic analyses. The rGO–Si delivered an initial discharge capacity of 1338.1 mA h g−1 with capacity retention of 87.1% after the 100th cycle at a current rate of 2100 mA g−1, and exhibited good rate capability. Such enhanced electrochemical performance is attributed to the synergistic effects of combining ultra-small silicon nanoparticles and rGO nanosheets. Here, rGO provides a continuous electron conducting network, whereas, ultra-small silicon particles reduce ionic diffusion path length and accommodate higher stress during volume expansion upon lithiation.