Mesoporous three dimension NiCo₂O₄/graphene composites fabricated by self-generated sacrificial template method for a greatly enhanced specific capacity

We reported a facile self-generated sacrificial template method for fabricating mesoporous three dimension NiCo₂O₄/graphene electrode material. Nickel, cobalt, and zinc ions dissolved in ethylene glycol reacted with potassium hydroxide solution to co-deposit onto graphene at 140 °C under atmospheric environment. With further addition of potassium hydroxide, zinc hydroxide as a self-generated sacrificial template was dissolved in situ, leading to the formation of mesoporous morphology. Structure and morphology characteristics were determined by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and N₂ adsorption experiments. Electrochemical properties were analyzed by AC impedance spectroscopy, cycling voltammetry, and charge/discharge test in 2 M KOH. Results showed that the as—prepared NiCo₂O₄/graphene electrode possessed a large specific surface area of 281.4 m² g⁻¹, an ultrahigh specific capacity of 1024.99 and 662.12 C g⁻¹ at current density of 1 and 50 A g⁻¹ respectively, and a long-term cycling life of 10,000 charge/discharge tests.