One-pot solvothermal synthesis of ZnFe2O4 nanospheres/graphene composites with improved lithium-storage performance

We report a facile one-pot solvothermal route for synthesizing ZnFe2O4/graphene nanocomposites. XRD, SEM and TEM results demonstrate that ZnFe2O4 nanospheres with a size of about 100-200 nm are uniformly dispersed on graphene nanosheets. Each ZnFe2O4 nanosphere is assembled by many nanoparticles around 10 nm. When evaluated as anode for Li-ion batteries, ZnFe2O4/graphene nanocomposites deliver a first discharge capacity of 1400 mAh g(-1) and remain a reversible capacity up to 704.2 mAh g(-1) after 50 cycles. ZnFe2O4/graphene nanocomposites also exhibit ameliorative rate capacity of 271.8 mAh g(-1) at the current of 800 mA g(-1), which can recover to 814 mAh g(-1) when the current density is reduced back to 100 mA g(-1). The enhanced electrochemical performances of the nanocomposites are ascribed to the confining and conducting effects of graphene and the synergistic effects between the conductive graphene and ZnFe2O4 nanospheres. (C) 2015 Elsevier Ltd. All rights reserved.