One-step synthesis method of flower-like Si@NiO/rGO composites as high-performance anode for lithium-ion batteries

Abstract

Si-based materials are the most potential high-capacity anode material for lithium-ion batteries due to their theoretical specific capacity of 4200 mAh g−1, significantly higher than the current commercial graphite anode (372 mAh g−1). However, the significant volume change (>300%) of Si-based materials during the embedding of lithium ions into Si NPs results in various issues, such as short cycle life and low electrical conductivity, which significantly restricts their commercial development. This study introduces a new flower-like Si@NiO/reduced graphene oxide (rGO) ternary composite synthesized using a straightforward and low-pollution one-step synthesis technique. A distinctive composite flower-like structure is created by wrapping Si NPs in NiO nanoflowers and embedding the rGO nanosheets in the NiO "petal" structure. This structure can shorten the lithium-ion transport path, provide a superb conductive network, effectively reduce the electrode's bulk effect and improve the structural stability of the anode material. Additionally, the structure provides more capacity for the electrodes. At a current density of 1 A g−1 and after 700 cycles, the Si@NiO/rGO anode displays a discharge-specific capacity of 1081.34 mAh g−1 thanks to its one-of-a-kind flower-like structure. At various current densities, the Si@NiO/rGO anode likewise demonstrates outstanding electrochemical performance. Additionally, the volume growth of the flower-like Si@NiO/rGO anode material after 700 cycles is approximately 15.08%, substantially less than that of Si NPs. The new flower-shaped Si@NiO/ rGO ternary composite, synthesized in a simple and cost-effective way, offers not only an alternative for the preparation of Si-based electrode materials that can alleviate their drastic volume expansion but also an effort to create new renewable green energy storage devices.