| 초록 |
The uniform diffusion of Si in a carbon matrix while retaining the morphology of Si is required to achieve higher performance lithium-ion batteries. Carbon-coated silicon nanoparticles embedded in monodisperse carbon spheres (C-SNP/ CSs) were congregated by a simple mixing method. We acquired high silicon contents up to 56 wt% for the composite electrodes. The C-SNP/CS anodes carried a reversible specific capacity of 1230 mAh/g for 56 wt% at 800 mAh/g after 150 cycles. The capacity retention after 150 cycles was 73% for the 56 wt% Si C-SNP/CS electrodes, while the uncovered C-SNPs displayed only 32% retention. The high cycle performance shows that the CSs effectively reduced the mechanical stress caused by the large volume changes of Si during the charge/discharge cycles. Furthermore, the high capacity retention discloses the high electrical conductivity of the electrodes, supplied by the congregated morphology the CSs and the carbon-shell on the silicon nanoparticles The use of CSs with C-SNPs is a facile method to acquire a uniformly-diffused compound and can be easily scaled for functional applications. |
