High capacity performance of NiCo₂O₄ nanostructures as a binder-free anode material for lithium-ion batteries

Recently, binder-free nanostructured materials provide a great opportunity for advanced lithium-ion batteries (LIBs) owing to their improved electrical conductivity with good porous structure. NiCo₂O₄ (NCO) nanostructures were successfully deposited on copper foam (CF) substrate to form porous three-dimensional (3D) NCO@CF hybrid structures via a simple solvothermal synthesis, followed by further heat treatment at 300°C (designated as NCO@CF-300) and 400°C (NCO@CF-400). The as-prepared samples revealed distinctly mixed morphologies of 2D nanosphere and nanowire-like structures, tuned by the further heat treatment. Both the electrodes could be explored as a binder-free anode for next-generation LIBs. It is demonstrated that the good integration of 2D morphology of NCO with 3D architectured CF has a significant effect on its electrochemical results. For the first cycle, binder-free NCO@CF-300 and NCO@CF-400 electrodes delivered the discharge capacity values of 1946 and 2637 mA h g⁻¹, respectively, at 500 mA g⁻¹. Moreover, the NCO@CF-300 electrode exhibited stable reversible capacity and good rate capability. From these results, the growth of NCO nanostructures on the CF can be suggested as a potential anode material for high-performance Li-ion batteries.