SnO2 and TiO2-supported-SnO2 lithium battery anodes with improved electrochemical performance

摘要

Li-ion battery anodes made of SnO2 nanoparticles and a TiO2-supported SnO2 nanocomposite formed of equimolar amounts of the Sn and Ti oxides were investigated, respectively. By limiting the voltage window of the charge/discharge cycles to the range 50 mV-1.0 V, both the SnO2-based anode and the SnO2/TiO2-based anode show improved cycling stability. Compared to the SnO2 nanoparticle based anodes, the TiO2-support-SnO2 nanocomposite anodes exhibit better cyclability and higher Coulombic efficiency. During the first lithiation process, Li~+ conducting Li_xTiO2 is formed in the SnO2/TiO2 composite, which structurally/mechanically supports the electrode. The anode made of amorphous TiO2-cassiterite SnO2 retained a reversible capacity of ～500 mAh g~(-1) based on the weight of SnO2) or ～320 mAh g~(-1) (based on the weight of SnO2/TiO2) at 0.2 C after 100 cycles and at a rate as fast as 5 C retained a stable reversible capacity of ～340 mAh g~(-1) (based on the weight of SnO2) or ～220 mAh g~(-1) (based on the weight of SnO2/TiO2).