Facile fabrication of three-dimensional porous carbon embedded with SnO2 nanoparticles as a high-performance anode for lithium-ion battery

A simple method was reported to fabricate a three-dimensional (3D) porous carbon through freeze drying followed by organic calcination. When the porous carbon is used as a matrix, the obtained SnO2/C composite with SnO2 nanoparticles (less than 8 nm) chemically bonded on the carbon surface by Sn–O-C exhibits more excellent electrochemical performance than bare SnO2. The SnO2/C electrode delivers a high initial reversible capacity of 854 mAh g−1 at 200 mA g−1 and remains at 287 mAh g−1 even after 100 cycles. Furthermore, with increasing current rate, the SnO2/C still restores a high capacity of 394 mAh g−1 at a higher current density of 2000 mA g−1, indicating its better rate capability than SnO2 (82 mAh g−1). The superior Li+ storage performance of SnO2/C can be resulted from the designed structure of composite as well as the 3D porous carbon. On one hand, the 3D porous carbon confining SnO2 nanoparticles in their localized regions by chemical bonding can buffer the volume expansion and shrinkage. On the other hand, the rich channels of 3D porous carbon can bring more paths for charge transfer, thus resulting in superior rate and cycling performance of SnO2/C composite.