Seong Ho Jung  Jae Seob Lee  Jung Sang Cho

10.7464/ksct.2024.30.3.220

Lithium-ion batteries Silicon anode Spray pyrolysis Pluronic-F127 Carbon coating

As the demand for lithium-ion batteries with high capacity and high energy density has rapidly increased, silicon anodes (theoretical capacity = 3,570 mA h g-1) have garnered attention as potential replacements for conventional graphite anodes (theoretical capacity = 372 mA h g-1). However, silicon anodes suffer from severe volume expansion (~360%) during lithiation, low ionic conductivity (10-14 ~ 10-13 cm2 S-1), and low electrical conductivity (10-2 S cm-1), resulting in poor cycling and rate performance. To address these issues, this study synthesized core@shell-structured silicon@carbon nanoparticles (Si@C NPs) via a one-pot spray pyrolysis process using Pluronic-F127. Pluronic-F127 in the spray solution contributes to the synthesis of nanoparticles by preventing the formation of silicon nanoparticle/dextrin agglomerates and by undergoing pyrolysis simultaneously. Additionally, dextrin derived amorphous carbon was coated on the surface of the silicon nanoparticles to act as an electron transport pathway within the anodes and enhance the electrical contact between the silicon nanoparticles. The Si@C NPs exhibited a discharge capacity of 1,912 mA h g-1 after 50 cycles at 1.0 A g-1 and high rate capabilities (discharge capacity of 1,493 mA h g-1 at 3.0 A g-1). The silicon@carbon composite nanoparticle synthesis strategy based on the spray pyrolysis process presented in this study is expected to offer a new direction for improving the performance of silicon anode materials.