Chiang Mai Journal of Science

     Lithium-ion batteries (LIBs) are chemically reactive rechargeable energy storages. Silica (SiO₂) is one of the most popular alternative materials to replace graphite as an anode material in LIBs due to its higher specific capacity, non-toxicity, and natural resources. Streblus asper Lour. (Khoi) is widely grown in Southeast Asia and contains high SiO₂ and SiO₂/C levels in its leaves. In order to overcome the volume change issue of Si-based materials and enhance cycle stability, carbon (C) and polypyrrole (PPy) were utilized to reinforce the SiO₂ structure during the lithiation/delithiation process. X-ray diffraction (XRD) was utilized to investigate the SiO₂, C, and PPy amorphous phases of the synthesized products. Fourier transform infrared spectroscopy (FT-IR), which confirmed the formation of PPy in composites. The scanning electron microscopy (SEM) images revealed different morphologies of SiO₂ aggregates, SiO₂/C with plate layers, the network structure of PPy and in the composites with PPy. Transmission electron microscopy (TEM) revealed the aggregation of nano-sized SiO₂, SAED phase confirmation, and demonstrated the coating of PPy on SiO₂/C (KSCPy composites), indicating the presence of C and PPy as supporters. In addition, the performance of synthesized composites as anodes was investigated by assembling them into half-coin cells and performing electrochemical tests. Khoi-SiO₂/C/PPy (KSCPy) obtained a specific capacity of 497.9 mA g⁻¹ for 400 cycles at 0.1 A g⁻¹ and the lowest charge transfer resistance. Furthermore, these materials have the potential to be used as sustainable anode materials in LIBs due to their use of natural materials, a non-toxic synthesis method, and C and PPy as both support materials and conductive polymers, which can enhance electrical performance as anode materials.