Advanced three-dimensional hierarchical Pr₆O₁₁@Ni-Co oxides-based core-shell electrodes for supercapacitance application

A facile solvothermal method is used to fabricate hierarchical core-shell nanostructures based on praseodymium, nickel and cobalt oxides supported on nickel foam. The Pr₆O₁₁ nanoparticles were first grown on the nickel foam and then utilized as a backbone for anchoring NiO, Co₃O₄ and NiCo₂O₄ nanostructures to form a core-shell structure. The core-shell electrodes exhibit superior electrochemical performance than single Pr₆O₁₁ nanoparticles electrodes. A superior specific capacitance of 1635 F/g at a current density of 0.5 mA/cm² with good cycling stability was obtained for the Pr₆O₁₁@NiCo₂O₄ electrode. Moreover, a solid-state supercapacitor was fabricated by assembling Pr₆O₁₁@NiCo₂O₄ electrodes using KOH/PVA as the solid electrolyte. The as-prepared solid-state device demonstrated impressive energy density of 6.6 W h/kg and a power density of 150 W/kg. This optimal performance could be attributed to the high conductive nickel foam current collector and synergistic effects generated from the core-shell architecture of NiCo₂O₄ and the Pr₆O₁₁ nanoparticles.