Facile fabrication of 3D porous NiO–NiCo₂O₄ film for superior lithium storage

We report a facile method to fabricate three-dimensional (3D) porous NiO–NiCo₂O₄ film on Ni foam substrate through the electrostatic spray deposition (ESD) technique followed by annealing in Ar atmosphere for lithium-ion battery anodes. The structure and morphology of NiO–NiCo₂O₄ film were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The NiO–NiCo₂O₄ electrode as a binder-free anode exhibits stable cycling performance with a reversible capacity of over 1466 mAh g⁻¹ after 100 cycles at a current density of 400 mA g⁻¹ and good rate capability. The superior lithium storage performance of the NiO–NiCo₂O₄ electrode is attributed to the unique porous NiO–NiCo₂O₄ structures directly deposited on Ni foam, which could provide more effective void space for the volume change, and offer more contact area between the electrolyte and the electrode, and improve the electron transport.