Na-Ions Diffusion Impacts Supercapacitor Performance for Amaryllis-like NiCo2O4 Nanostructures.

NiCo2O4 nanomaterials with exceptional electrochemical performances are synthesized via a simple and low-cost method. The synthesized nanostructures exhibit a high specific surface area of 121.52 m2 g-1 and excellent specific capacitance of 2498.49 F g-1 at a current density of 2 A g-1, an energy density of 79 Wh kg-1, and power density of 3570 W kg-1. The remarkable cycling stability of 92.61% retention after 5000 cycles demonstrates that NiCo2O4 nanomaterials have a potential for practical application in energy storage devices. The Na+ ion diffusion (by VASP) affirms a low activation energy barrier for Na ion intercalations onto the electrode material, illuminating excellent electrochemical performances.