Enhanced cyclability of amorphous carbon-coated SnO2-graphene composite as anode for Li-ion batteries

This paper reports an amorphous carbon-coated SnO2-graphene composite (C@SnO2-Gr) which shows excellent cyclability and a high specific capacity used as an anode for the Li-ion batteries. The C@SnO2-Gr maintained a specific capacity of 879 mAh g(-1) after 50 cycles at a current density of 100 mA g(-1). After 350 cycles at a high current density of 1200 mA g(-1), the specific capacity was resumed to around 860 mAh g(-1) when the current density dropped to 100 mA g(-1). It is proved that the excellent electrochemical performance is mainly related to the unique 'core-shell' structure induced by the carbon coating. This structure significantly alleviated the pulverization problems of the electrode materials, maintained the microstructure of electrodes and stabilized Sn nanoparticles in the form of nanocrystallites. Graphene and amorphous carbon also provide good conductivity to the active materials. This work suggests that carbon coating is an effective way to improve the electrochemical performance of graphene-metal oxide as anode for Li-ion batteries by means of improving the stability of the nanocrystalline structure. (C) 2014 Elsevier Ltd. All rights reserved.