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

Highlights: • A one-pot solvothermal route is developed for synthesizing ZnFe{sub 2}O{sub 4}/graphene nanocomposites. • ZnFe{sub 2}O{sub 4} nanospheres with a size of about 100–200 nm are uniformly dispersed on graphene nanosheets. • The nanocomposite delivers a reversible capacity of 704 mAh/g after 50 cycles. • The improved lithium-storage performance is ascribed to the confining and conducting effects of graphene nanosheets. - Abstract: We report a facile one-pot solvothermal route for synthesizing ZnFe{sub 2}O{sub 4}/graphene nanocomposites. XRD, SEM and TEM results demonstrate that ZnFe{sub 2}O{sub 4} nanospheres with a size of about 100–200 nm are uniformly dispersed on graphene nanosheets. Each ZnFe{sub 2}O{sub 4} nanosphere is assembled by many nanoparticles around 10 nm. When evaluated as anode for Li-ion batteries, ZnFe{sub 2}O{sub 4}/graphene nanocomposites deliver a first discharge capacity of 1400 mAh g{sup −1} and remain a reversible capacity up to 704.2 mAh g{sup −1} after 50 cycles. ZnFe{sub 2}O{sub 4}/graphene nanocomposites also exhibit ameliorative rate capacity of 271.8 mAh g{sup −1} at the current of 800 mA g{sup −1}, which can recover to 814 mAh g{sup −1} when the current density is reduced back to 100 mA g{sup −1}. The enhanced electrochemical performances of the nanocomposites are ascribed tomore » the confining and conducting effects of graphene and the synergistic effects between the conductive graphene and ZnFe{sub 2}O{sub 4} nanospheres.« less