The effects of binders on the lithium storage of Fe3O4/NiO heterostructures

Fe3O4 and Fe3O4/NiO heterostructures were successfully prepared by a simple one-step solvothermal method. The morphology of Fe3O4/NiO heterostructures is flower-like spheres composed of nanosheets with a thickness of 10–20 nm. As anode material for lithium-ion batteries (LIBs), the electrochemical performance of the Fe3O4 and Fe3O4/NiO heterostructures are comparatively investigated. At current density of 100 mA g−1, the Fe3O4/NiO heterostructures can maintain 1021 mAh g−1 after 100 cycles. The discharge capacity can still maintain at 500 mAh g−1 and the coulomb efficiency is always stable at 99.6% after 1000 cycles at 1 A g−1. The Fe3O4/NiO heterostructures also have lower impedance and better rate capability, compared with the bare Fe3O4 electrode. Moreover, the electrochemical properties of the Fe3O4/NiO heterostructures can be further improved when the new binder CMC-Li is used. At 100 mA g−1, it can still maintain 1544 mAh g−1 after 100 cycles. These loose-layered nanosheets can effectively alleviate the volume expansion of materials in the process of charge and discharge. Meanwhile, the large surface area can provide more reaction sites. The ultra-thin nanosheet can also reduce the diffusion distance of lithium ions, so that the Fe3O4/NiO heterostructures have excellent performance in lithium-ion batteries.