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

Abstract

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).