Microstructures and electrochemical properties of a SiO1.39-C composite for a lithium-ion secondary battery

SiO1.39 nanoparticles synthesized by using an evaporation and condensation process were composited with phenol resin and conducting carbon (C), and their microstructures and electrochemical properties were investigated. A dense, micro-sized SiO1.39-C composite was synthesized to prevent capacity fading of the SiO (x) nanoparticles. To densify and coarsen this composite, we carried out pelletizing, annealing and crushing of the sample. The electrical conductivity was also improved by the composition without any structural change. Crushed particles were used as an anode material for a Li-ion battery, and its cyclic performance was evaluated. By composition, the coulombic efficiency was observed to increase from 93.6 to 97.5% at the 5 (th) cycle, and it continued increasing with each additional cycle. For the composite annealed at 1,000 A degrees C in a 4-vol.% H-2/Ar atmosphere, the specific capacity and the coulombic efficiency at the 20 (th) cycle were measured as 426 mAhg(-1) and 99.7%, respectively.