Enhanced Li storage capacity in 3 nm diameter SnO₂ nanocrystals firmly anchored on multiwalled carbon nanotubes

A simple synthesis route is demonstrated for the preparation of hybrid nanocomposite electrodes with a combination of SnO₂ nanoparticles and conducting multiwalled carbon nanotubes (MWCNTs) for Li ion battery applications. The MWCNTs were initially treated using strong acid solutions to generate functional groups with negative charges on their surfaces. For the formation of the nanocomposites, the next process was driven by the mutual electrostatic interactions between the functionalized MWCNTs and the Sn ⁴⁺ ion species and was followed by spontaneous oxidation during a hydrothermal reaction at 150 °C. The SnO₂ nanoparticles with diameters of less than 3 nm were uniformly loaded onto the MWCNT surfaces, providing an extremely large Brunauer-Emmett-Teller (BET) surface area of ∼240 m² g^-1. Furthermore, we demonstrate that the incorporation of multiwalled carbon nanotubes gives rise to an enhanced reversible capacity estimated to be 420 mA h g^-1 after 100 cycles, which is at least three times greater than that of pure SnO₂ nanoparticles.