One-step synthesis of SnOx nanocrystalline aggregates encapsulated by amorphous TiO2 as an anode in Li-ion battery

SnOx nanocrystalline aggregates (NAs) encapsulated by an amorphous TiO2 layer have been successfully designed by a one-step flame spray pyrolysis (FSP). The synthesized SnOx NAs@TiO2 with different degrees of aggregations were composed of SnOx nanocrystallites ranging from 5 nm to 10 nm and a TiO2 layer with a thickness of 1-5 nm. The encapsulated TiO2 layer was introduced in situ by incorporating TiCl4 into the downstream of an FSP reactor, where TiO2 nucleated and grew in the surface of the SnOx NAs. The hydrolysis temperature of TiCl4 in a flame was controlled to synthesize amorphous TiO2 with intrinsic electrochemical features. As an anode in LIBs (Li-ion batteries), the SnOx NAs@TiO2 electrode showed superior cycle life and rate performance (capacity of 350 mA h g(-1) after 300 cycles and 332 mA h g(-1) at 1 A g(-1)) compared to pure SnOx or TiO2 electrodes. The remarkably enhanced Li+ storage performance is mainly attributed to the nanoscale of nanocrystalline aggregates, the core-shell structure of SnOx@TiO2 and the amorphous state of TiO2.