High Performance Silicon-Carbon Composite Powders Using Recycled Silicon from Solar Cells As Anode Material for Li-Ion Batteries

Currently, silicon (Si) coming from the recycling of solar cells is a non-valued fraction. The principal aim of this work is the development of silicon recovered during the dismantling of solar panels as negative electrode material for Li-ion batteries. The principal technological challenge associated with the use of silicon in this type of application is to control the volume expansion during charge/discharge cycles. This drawback can be avoided through the formation of Silicon/carbon composites in which the size of the silicon particles and their dispersion is controlled.
In this research, we develop a carbon matrix system using a conducting carbon source and a reduced carbon from organic source that will incorporate the silicon particles. The recycled Si wafers are leached to remove Al and Ag. The grinding step is performed to obtain Si particles of <200nm and then a mixed suspension of Si, an organic carbon source and the conductive carbon source is prepared. This mixture is spray-dried followed by heat treatment to generate a carbon matrix that incorporates the silicon particles
The morphology of the composite materials is analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Electrochemical performance of Si/C composites is characterized by Galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy (EIS).