Efficient and swift heating technique for crafting highly graphitized carbon and crystalline silicon (Si@GC) composite anodes for lithium-ion batteries

The synthesis of battery materials from biomass as feedstock is not only effective but also aligns with sustainable practices. However, current methods like slow pyrolysis/heating are both energy-intensive and economically impractical. Hence, integrating energy-efficient technologies becomes imperative to curtail substantial energy consumption and, consequently, minimize carbon dioxide (CO₂) emissions during electricity usage. Herein, we employed a one-step pyrolysis/reduction based on the microwave heating method to synthesize a composite of high-purity silicon and highly graphitized carbon (Si@GC) from rice husk as feedstock. Compared to the conventional heating methods, the Si@GC samples prepared via the microwave heating method required less time (30–50 min). Benefiting from ultrahigh heating rates, the highly graphitized carbon and crystalline silicon composite was successfully synthesized. The synthesis by microwave irradiation showed homogenous material, excellent surface area, essential functional groups, and crystallinity revealing the outstanding reaction kinetics to form the material. The as-synthesized Si@GC composite anode material delivered a high discharge capacity of 799 mAh/g with high cyclic stability of ~71% over 120 cycles. The ex situ ToF-SIMS revealed great inorganic SEI composition, mainly consisting of the fluorinated species and carbonate species produced at the initial cycle. This investigation provides a novel rapid heating method for the synthesis of battery materials, which can also be extended for other materials and applications.