There-dimensional porous carbon network encapsulated SnO₂ quantum dots as anode materials for high-rate lithium ion batteries

SnO₂ quantum dots have attracted enormous interest, since they have been shown to effectively minimize the volume change stress, improve the anode kinetic and shorten the lithium ion migration distance when used as anode materials for lithium ion battery. In this work, we report a facile strategy to fabricate nanostructure with homogenous SnO₂ quantum dots anchored on three-dimensional (3D) nitrogen and sulfur dual-doped porous carbon (NSGC@SnO₂). Characterization results show that the obtained SnO₂ quantum dots have an average critical size of 3–5 nm and uniformly encapsulated in the porous of NSGC matrix. The as-designed nanostructure can effectively avoid the aggregation of SnO₂ quantum dots as well as accommodate the mechanical stress induced by the volume change of SnO₂ quantum dots and thus maintain the structure integrity of the electrode. As a result, the obtained NSGC@SnO₂ composite exhibits a specific reversible capacity as high as 1118 mAh g⁻¹ at a current of 200 mA g⁻¹ after 100 cycles along with a high coulombic efficiency of 98% and excellent rate capability.