Three-dimensional Li2O-NiO-CoO composite thin-film anode with network structure for lithium-ion batteries
Three-dimensional Li2O–NiO–CoO composite thin-film electrodes deposited on stainless steel substrates were synthesized by the electrostatic spray deposition (ESD) technique at 240 and 295 °C. The morphology of the composite was investigated by scanning electron microscopy. X-ray diffraction indicated that the as-deposited films are composites of Li2O, NiO and CoO. The effects of the solvent used to dissolve the starting materials on the morphology and electrochemical performance of the thin-film electrodes were also investigated. It was found that the as-deposited thin-film electrodes exhibited a high reversible capacity (>800 mAh g−1 when cycled between 0.01 and 3 V at a cycling rate of 0.5 C), good capacity retention, and outstanding rate capability. The superior electrochemical performance may have resulted from the combination of the very porous structure and the three-dimensional network of the as-deposited thin-film electrodes, which contributed to a high surface area, favoured lithium-ion diffusion, and formed a stable integral structure. The thin-film electrodes could be promising anodes for use in high power and high energy density lithium-ion batteries.