3D Graphene Encapsulated Hollow CoSnO 3 Nanoboxes as a High Initial Coulombic Efficiency and Lithium Storage Capacity Anode

3D Graphene sheets encapsulated amorphous hollow CoSnO 3 nanoboxes (H‐CoSnO 3 @reduced graphene oxide [RGO]) are successfully fabricated by first preparing 3D graphene oxides encapsulated solid CoSn(OH) 6 nanocubes, followed by an alkaline etching process and subsequent heating treatment in Ar. The hollow CoSnO 3 nanoboxes with average particle size of 230 nm are uniformly and tightly encapsulated by RGO sheets. As an anode material for Li‐ion batteries, H‐CoSnO 3 @RGO displays high initial Coulombic efficiency of 87.1% and large reversible capacity of 1919 mA h g −1 after 500 cycles at the current density of 500 mA g −1 . Moreover, excellent rate capability (1250, 1188, 1141, 1115, 1086, 952, 736, and 528 mA h g −1 at 100, 200, 300, 400, 500, 1000, 2000, and 5000 mA g −1 , respectively) is acquired. The reasons for excellent lithium storage properties of H‐CoSnO 3 @RGO are discussed in detail.