Fabrication of Pomegranate-Shaped Silicon Microparticles Using Ultrasonic Spray Pyrolysis

Silicon nanoparticles have attracted considerable attention as high-capacity anode materials for lithium ion batteries. However, the high specific surface area of nanoparticles results in excessive formation of the solid electrolyte interphase, leading to limitations in achieving high energy density. To overcome these limitations, pomegranate-shaped silica microparticles composed of aggregated silica nanoparticles were prepared using ultrasonic spray pyrolysis. Spherical silica nano sols with sizes ranging from 60 to 90 nm were employed as a precursor for the ultrasonic spray pyrolysis, yielding pomegranate-shaped silica microparticles. Subsequent magnesiothermic reduction and acid leaching converted silica into the silicon phase. The resulting silicon microparticles maintained a mean particle size of 2.37 μm with an average internal pore diameter of approximately 30 nm, preserving the structural morphology. Electrochemical evaluation revealed initial charge and discharge capacities of 3179 and 2416 mAh g−1, respectively. After 50 cycles, the discharge capacity stabilized at 500.9 mAh g−1.