Scalable synthesis of ultrasmall SnO2 nanocrystals in carbon conductive matrices: High loading and excellent electrochemical performance

Ultrasmall sub-5 nm SnO2 nanocrystals/carbon composites, with the SnO2 loading as high as 87.3 wt%, are synthesized via a facile hydrothermal route, followed by calcination. The annealed SnO2/C composite shows a higher discharge capacity and superior rate performance, compared with the pristine SnO2/C sample. At the current density of 200 mA g−1, it can deliver a high reversible capacity of 968 mAh g−1. When the current density increases to 5000 mA g−1, a high discharge capacity of 435 mAh g−1 can still be obtained, much higher than the theoretical capacity of graphite. Our results indicate the potential suitability of synthesizing ultrasmall electrode nanocrystals with high electrochemical performance.