High–performance recycled silicon–based Li–ion battery anodes enabled by Si/C composites engineering and graphene oxide protective layer

Silicon (Si) has emerged as viable alternative to the commercial graphite anode active material (AAM) in lithium–ion batteries (LIBs). To ensure the implementation of Si in practical applications, significant improvements in its electrochemical performance are needed. Here we developed Silicon/carbon (Si/C) composites as AAM for LIBs using Si sourced from end–of–life (EoL) solar cells. The electrode design comprises the engineering of Si/C composites produced at pilot scale along with a graphene oxide (GO) layer covering the electrode. The Si/C composite demonstrates hollow spherical particle structure designed to shelter the Si particles from the pulverization caused by the volume expansion/shrinkage during cycling. This innovative design along with the GO protective layer, leads to robust Si particles enabling the formation of stable solid electrolyte interface (SEI). In-situ electrochemical impedance spectroscopy and galvanostatic intermittent titration technique measurements confirmed the crucial role of the GO coating in enhancing the electrochemical properties. Si/C electrode exhibits outstanding electrochemical performance showcasing a high specific capacity of 1200 mAh.g −1 (with capacity limitation set at 1200 mAh.g −1 ), while maintaining the capacity retention of 99.99 % over extended cycling time of 1500 cycles. Moreover, the electrode delivers remarkable specific capacity of 2000 mAh.g −1 over 250 cycles without any capacity limitation. • Si/C anode material was prepared at pilot scale using spray drying method. • Electrode performance was boosted by an innovative graphene oxide layer. • Si/C electrode presents excellent electrochemical performance.