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

• A one-pot solvothermal route is developed for synthesizing ZnFe2O4/graphene nanocomposites.
• ZnFe2O4 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.

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.

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