A Study on the Buffering Role of Graphene in SnO2

For an anode material in LIBs, SnO2 anode has attracted special attention because of its high theoretical energy density (ca.780mAh g-1) over conventional graphite (ca.372mAh g-1). However, SnO2 anode materials usually suffer from capacity fading since SnO2 undergoes dramatic volume expansion (ca. 370%) during lithium ion insertion and extraction process, which results in stress induced pulverization of electrode and breakdown of electronic conductivity network. SnO2-conductive carbon matrix composites have been widely studied to overcome these obstacles. Especially, SnO2/graphene composites reportedly could improve cycle performances, since graphene might buffer the specific volume changes of electrodes. 1-2 However, there has been no reports which provided direct evidence