Sn nanocrystals embedded in porous TiO2/C with improved capacity for sodium-ion batteries
Sn-based materials attract increasing attention for application in sodium-ion batteries (SIBs), due to the ultra-high theoretical capacity of pure Sn. However, the low structural stability and poor rate capability restrict their further development. Herein, a facile method is reported to embed Sn nanocrystals into TiO2/porous carbon (TiO2/C) composite via direct carbonizing the mixture of tetraphenyltin and Ti-based metal-organic framework. The obtained cylinder-like Sn/TiO2/porous carbon (Sn/TiO2/C) composite is uniformly built by TiO2 nanoparticles, Sn nanocrystals and N-doped carbon. Importantly, pores, formed by the accumulation of nanoparticles, can effectively restrict the huge volume change of Sn during cycling. When evaluated as an anode in SIBs, the Sn/TiO2/C not only possesses amazing cycling stability (159.6 mAh g-1 at 1.0 A g-1 after 3000 cycles), but also exhibits excellent rate performance (172.3 mAh g-1 at 1.0 A g-1 and 114.0 mAh g-1 at 10.0 A g-1). These superior properties can be attributed to Sn nanocrystals for enhanced specific capacity and electrical conductivity, and TiO2/C substrate for improved structural stability and facilitating charge transfer kinetics.