| 초록 |
Highly ordered mesoporous SnO2 with residual silica were successfully synthesized from a mesoporous silica template (SBA-15) via nano-replication method. A tin precursor, SnCl22H2O, was infiltrated spontaneously within the mesopores of the silica templates by melting the precursor at 353 K without using a solvent. After the heat-treatment of composite materials at 973 K under static air conditions, the controlled removal of silica templates using NaOH or HF solutions with different concentrations results in the successful preparation of mesoporous SnO2, where has the amounts of residual silica species. The residual silica species induce a nano-propping effect enabling the mesoporous SnO2 to remain stable up to 973 K without any structural collapse. More importantly, the optimum amount of residual silica species results in a dramatic reduction in capacity fading after prolonged cycles in Li-ion battery. The mesoporous SnO2 with 3.9 wt% of silica still exhibits a large capacity (about 600 mAh g-1) after the 30th cycle, which is probably because the residual silica species act as a physical barrier to suppress the aggregation of Sn clusters formed in the mesoporous SnO2 during the lithium storage. |
