Silicon-Based Composite Negative Electrode Prepared from Recycled Silicon-Slicing Slurries and Lignin/Lignocellulose for Li-Ion Cells

A large amount of kerf loss silicon slurries has been produced in the photovoltaics industry by direct diamond-wire slicing. The high-purity silicon particles in the slurries are suitable for reutilization as anode materials for lithium-ion batteries. In this study silicon particles from the kerf loss of silicon ingot slicing, coupled with lignin or lignocellulose as carbon precursors, are employed to form carbon-silicon composite materials. A pyrolysis thermal treatment in the presence of argon was applied to carbonize the biomass on the silicon materials in order to increase the conductivity of silicon-based anodes. Due to the different carbonaceous precursors, the composites formed different structures. The lignin-silicon electrode with a carbon-coated structure delivered an initial charge capacity of up to 2286 mAh/g and retained 880 mAh/g after 51 cycles at 300 mA/g. On the other hand, the pyrolyzed lignocellulose formed an interconnected structure with silicon particles, providing extra space to accommodate Si volume variation. The composite electrode exhibited an outstanding cycle performance with a capacity retention of up to 83.4% after 51 cycles at 300 mA/g. It was found that the utilization of silicon slurries from industrial silicon kerf loss and of biomass resources as battery materials can be improved and applied in energy storage application.