Dual carbon protected SnO2 with superior lithium storage performance

Due to the high theoretical capacity, SnO2 was considered as a prospective anode for the new-generation lithium-ion batteries. Here, a novel dual carbon protection strategy for fabricating a carbon-based framework for SnO2 materials, in which the SnO2 nanoparticles were encapsulated in the N-doped carbon and well decorared on a macroporous graphene framework (NC@SnO2/G). As an anode, the CN@SnO2/G exhibits preferable energy storage properties compared with the pure SnO2 and SnO2/graphene. The NC@SnO2/G delivers not only a higher capacity of 974.9 mAh g(-1) at 0.5 A g(-1) (350 cycles), but also an excellent rate capability of 418.1 mAh g(-1) even at 3 A g(-1). Such superb performance could be assigned to the nanosize of SnO2 decrease the ions transport length and increase active sites, the macroporous graphene framework faciliate the electrolyte penetration and buffer volumne change, the N-doped carbon coating could facilitate formation stable solid electrolyte interface (SEI), prevent the imtermediate Sn agglomeration, and improve the conductivity. This work could be extended to other metal oxide/carbon composites with high energy storage performance.