Development of novel mesoporous C-TiO2-SnO2 nanocomposites and their application to anode materials in lithium ion secondary batteries

摘要

Herein, we employed the tetra-constituent co-assembly method based on the acid-base pair of Sn and Ti precursors. Using this method, novel mesoporous carbon-TiO2-SnO2 nanocomposite materials were prepared and their structural change with an increase of SnO2 amount was investigated. In low amount of SnO2, an ordered mesoporous structure was observed but it became collapsed at 64 wt.% SnO2, while crystal size of anatase TiO2 embedded within amorphous SnO2 and carbon matrix became larger. When applied to anode materials in lithium ion batteries, an increase of the reaction peaks of Li~+ in SnO2 was observed and peak associated with discharging in TiO2 nano-crystal increased in spite of lower amount of TiO2. This indicated that TiO2 was highly utilized for lithium storage (275 mAh g~(-1) in 19.9 wt.% TiO2 case). In the nanocomposite electrode with 28.8% TiO2, however, a high rate performance and a very stable cycle performance (95.3% retention at 40th cycles) were observed, which was attributed to the stable nanostructure.