Assembly of SnO2 quantum dots on RGO to form SnO2/N doped RGO as a high-capacity anode material for lithium ion batteriesElectronic supplementary information (ESI) available: Experimental details, TGA curves, XRD patterns, and XPS spectra of SnO2/N doped RGO. See DOI: 10.1039/c4ce02315c

We demonstrate a fast and facile ultrasound-assisted method for the synthesis of ultrasmall SnO 2 quantum dots with an average particle size of 3 nm followed by a self-assembly process on reduced graphene oxide nanosheets (RGO) to build a high-capacity anode material for lithium ion batteries (LIB). The bifunctional aminocaproic acid (AHA) plays a key role in our synthesis. It not only protected the ultrasmall SnO 2 nanocrystals but also changed the SnO 2 surface potential to +41.4 eV. More importantly, AHA was also used as a nitrogen source. It opens a new window to use this simple and low-cost method to fabricate complex graphene-based hybrid nanomaterials. An ultra-fast and facile ultrasound-assisted method has been successfully developed for the synthesis of ultra-high quality SnO 2 quantum dots.