Room-temperature synthesis of colloidal SnO₂ quantum dot solution and ex-situ deposition on carbon nanotubes as anode materials for lithium ion batteries

Colloidal SnO₂ quantum dots (QDs) have been successfully prepared via a facile aqueous wet-chemical synthetic approach using tin dichloride as tin source and thiourea as accelerating and stabilizing agent under magnetic stirring at room temperature. The SnO₂ QDs with average size of ∼3.5 nm are well-dispersed in the aqueous solution with high stability. A facile ex-situ deposition of SnO₂ QDs on carbon nanotubes (CNTs) is developed, allowing large loading amount of SnO₂ QDs on the CNTs with uniform distribution. When used as anode material for lithium ion batteries, the as-prepared SnO₂-CNT nanocomposites exhibit superior lithium storage properties, delivering a stable discharge capacity of 845 mAh/g at 100 mA/g after 90 cycles. More importantly, the novel synthetic strategy is promising for the cost-effective and large-scale fabrication of SnO₂-CNT nanocomposites as high-performance anodes for electrochemical energy-storage.