Layer structured graphene/porous ZnCo2O4 composite film for high performance flexible lithium-ion batteries

There is growing interest in flexible and reliable energy storage devices to meet the special needs for next-generation flexible electronics. In this work, graphene/porous ZnCo2O4 composite film with unique layered nanostructure is fabricated. The ZnCo2O4 nanocrystallites in the composite film randomly interconnected with each other in the 2D plane to form unique sheet-like morphology with a large number of nanopores, which are further sandwiched by graphene sheets. When it is evaluated as the anode material in lithium-ion half cells, this hybrid film electrode shows high electrochemical performance with a charge capacity of 874 mAh g(-1) at 100 mA g(-1), and demonstrates excellent cycling stability with only 2.7% capacity loss after 1000 cycles at 1 Ag-1. Furthermore, a flexible full battery using the free-standing graphene/porous ZnCo2O4 film as the anode is fabricated in pouch form. The excellent electrical conductivity and porous nanostructure of the hybrid film electrode enable rapid electron and ion transport. Thus, the flexible full battery exhibits good flexibility and superior electrochemical performances simultaneously.