Sustainable Mechanochemical Processed Recycled Spent Graphite and Nano-Silicon Composites as Anode for Advanced Li-Ion Batteries

Abstract

Advanced lithium-ion batteries (LIBs) for electric vehicle applications are on demand recently. Graphite anode in LIBs provides with good cycle life but limited capacity. On the other hand, silicon that possesses high capacity but significant volume changes during cycling limits its practical use. Hence, nanocomposites of graphite and nano silicon (nSi) can provide a viable solution. This work emphasizes the potential of recycled spent graphite (SG) composited with nSi anode in order to fulfill the demand for high capacity anodes. SG to nSi ratio is systematically designed of the composite for LIB applications. The structural, morphological, and surface chemical analysis are conducted and further correlated with the electrochemical performances of the composite anodes. The nanocomposite with equal ratio of SG:nSi (1:1) exhibited high reversible capacity of 1886 mAh g⁻¹ while the SG dominant ratio of SG:nSi (3:1) delivered a least capacity loss of less than 2.2 mAh g⁻¹ cycle⁻¹ for 200 cycles. Nanocomposites exhibited satisfactory electrochemical performance; especially improving cycling stability. The enhanced performance is attributed to the stable solid-electrolyte interface layer formation which is further characterized by ex situ X-ray Photoelectron Spectroscopy analysis with different state of charge and discharge conditions.