Monodisperse SnO2 nanocrystals functionalized multiwalled carbon nanotubes for large rate and long lifespan anode materials in lithium ion batteries

A facile way towards high rate and long lifespan anode materials based on SnO2 and commercial multiwalled carbon nanotubes (MWCNTs) is readily achieved through a combination of activation and hydrothermal treatment. The former endows the MWCNTs with abundant hydrophilic radicals, while the latter guarantees intimate connection between SnO2 and MWCNTs; eventually, monodisperse SnO2 nanocrystals ca. 3 nm are firmly anchored on the MWCNTs without agglomeration. When used for lithium ion batteries (LIBs) anodes, the hybrid composite exhibits excellent cycling capability with high reversible capacity about 700 mAh g−1 (based on total weight of the composite) for 150 cycles at 0.1 A g−1 superior to both components involved. Besides large rates of 5 A g−1 with recoverable initial reversible capacity, it also last for more than 1000 cycles with little capacity decay, outperforming most SnO2 based carbon nanotubes composites (SnO2/CNTs) so far. Insights into the electrochemical processes reveal the hybrid composite exhibits enhanced redox capacitance and interfacial capacitance in comparison with SnO2 nanocrystals which indicate the perfect interfaces and robust structure of the hybrid composite.