Spherical Gr/Si/GO/C composite as High-Performance Anode Material for Lithium-Ion Batteries

Silicon (Si) has been considered as the most promising anode material for next generation lithium-ion batteries (LIBs) due to its ultrahigh theoretical specific capacity (4,200 mAh g(-1)) and volume capacity (9,786 mAh cm(-3)), relatively low operating voltage (similar to 0.5 V vs Li+/Li), the abundant natural Si source, and environmental benignity. However, the huge volume expansion and poor conductivity limit seriously the electrochemical reversibility and cycling stability of silicon-based anode materials, and thus hinder their commercial application. To address these issues, herein we put forward a strategy to prepare the spherical graphite/silicon/graphene oxides/carbon (Gr/Si/GO/C) composite by electrostatic self-assembly and spray drying process. The structure and morphology of the as-prepared samples are characterized by X-ray diffraction (XRD), Raman spectrum, Fourier transform infrared spectroscope (FTIR), scanning electron microscope (SEM), electron backscatter diffractometer (EBSD), and transmission electron microscope (TEM). The results show that the as-synthesized Gr/Si/GO/C composite has a high discharge capacity of 1212.0 mAh g(-1) at 200 mA g(-1) with the initial Coulombic efficiency (ICE) of 80.4%, and the capacity retention rate is 81.7% after 100 cycles. Apparently, the as-prepared spherical Gr/Si/GO/C composite can well buffer the volume expansion of silicon, maintain the structural integrity of the electrode, enhance stability by reducing silicon aggregation, and promote the electric and ionic conductivity as well Li storage ability. Therefore, this strategy of reasonable structure design provides a beneficial exploration for the large-scale industrial application of silicon-based anode materials.