A novel Si@C structure interwoven with Si composite nanowires catalyzed by Cu nano particles and its performances as an anode for LIBs

Abstract

As a promising anode for the next-generation lithium-ion batteries (LIBs), Si@C with the core–shell structure has attracted widespread attention due to its high theoretical capacity. Carbon (C) shell is usually composed of disordered C, hindering the electrons to pass through. In this study, the submicron silicon (Si) waste in the kerf waste from the photovoltaic industry was recycled as raw materials, and a novel Si@C structure interwoven with Si composite nanowires was synthesized under the catalysis of copper (Cu) nanoparticles. As a result, the as-prepared Si@C–Cu anode possessed an initial capacity of 3323.3 mA h g⁻¹ with a coulombic efficiency of 70.0% and retained a specific capacity of 1019.0 mA h g⁻¹ after 1000 cycles at a current density of 0.2C (1C = 4200 mA g⁻¹). In addition, in rate testing, it can maintain 1685.2 mA h g⁻¹ at 1.0C and 867.7 mA h g⁻¹ at 4.0C, and it still retained 3000 mA h g⁻¹ when the current density was restored to 0.1C. A reasonable mechanism for forming Si composite nanowires can be the dissolution/reprecipitation of Si in/out of Cu. It suggested that the as-prepared Si@C–Cu nanostructure could achieve a high electrochemical performance as an anode for LIBs.