Graphene-encapsulated ZnO composites as high-performance anode materials for lithium ion batteries

Composites of graphene-encapsulated ZnO particles (ZnO/rGO) have been produced through a simple yet effective spray drying method followed by a heating treatment in inert atmosphere. The graphene-coated structure can guarantee good structural stability and rapid ionic transport of the composites. The influences of drying methods, graphene contents, and precursors of ZnO on the morphology, particles size, and electrochemical properties of the resulted composites have been investigated. When they are used as anode materials for lithium ion batteries, the optimized ZnO/rGO composite achieves a high initial Coulombic efficiency of 69.8%, and it maintains a reversible specific discharge capacity of 793 mA h g−1 after 200 cycles at 100 mA g−1, 608 mA h g−1 after 250 cycles at 200 mA g−1, and 327 mA h g−1 after 450 cycles at 500 mA g−1, respectively.