Natural Graphite reinforced with Si@TiO2 core-shell nanoparticles as anode for Li-ion batteries

Abstract Commercial Li-ion batteries rely on anodes made of graphite, but low specific capacity (372 mAh/g) of graphite restricts its usage in high-energy demand applications. Literature suggests that Si has a high specific capacity (4200 mAh/g), but huge volume expansion during the electrochemical process leads to fast capacity decay. This work deals with the development of graphite-based composite material with the potential to be used as an anode. Adopting the structural modification approach and co-utilization strategy, the composite material is developed through graphite reinforcement with the developed core-shell nanoparticles (Si@TiO2). Si@TiO2 nanoparticles are synthesized to develop a thin coating layer (≈ 5 nm) of TiO2 on Si using the peptization technique. The developed materials are characterized using FESEM, EDS, TEM, XPS, and XRD. Further, electrochemical response of the developed composite material is recorded using Cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), and Galvanostatic charge/discharge test (GCD). Compared with graphite, the developed composite anode exhibits improved specific capacity with a small percentage (10%) mixing of core-shell nanoparticles into graphite. The composite anode demonstrates stable electrochemical behavior. The initial specific capacity attains the value of ≈ 657 mAh/g at 1C, and 87% capacity retention has been observed after 100 cycles. Furthermore, developed composite shows good capacity retention at higher C-rate values.