Facile and eco-friendly synthesis of finger-like Co₃O₄ nanorods for electrochemical energy storage

Co₃O₄ nanorods were prepared by a facile hydrothermal method. Eco-friendly deionized water rather than organic solvent was used as the hydrothermal media. The as-prepared Co₃O₄ nanorods are composed of many nanoparticles of 30–50 nm in diameter, forming a finger-like morphology. The Co₃O₄ electrode shows a specific capacitance of 265 F g⁻¹ at 2 mV s⁻¹ in a supercapacitor and delivers an initial specific ischarge capacity as high as 1171 mAh g⁻¹ at a current density of 50 mA g⁻¹ in a lithium ion battery. Excellent cycling stability and electrochemical reversibility of the Co₃O₄ electrode were also obtained.