Preparation and Electrochemical Properties of Nickel Iron Carbonate Hydroxide as a Cathode Electrode Material for Asymmetric Supercapacitors

3D Binary NiFe(CO3)(OH)(2) nanosheet arrays were grown directly on porous Ni-foam using a facile hydrothermal method and applied as a binder-free electrode for high-performance supercapacitors. The composites of Ni and Fe ions exhibited excellent electrochemical performance due to the suitable particle size and good dispersion property of the NiFe-material electrode. In this study, NiFe(CO3)(OH)(2) nanosheet arrays were examined with different Ni/Fe reactant ratios. Among these samples, the optimized NiFe(CO3)(OH)(2) nanosheet composites (6 mmol Ni and 5 mmol Fe)exhibited a remarkable maximum specific capacitance of 686.6 F g(-1) at 3 A g(-1), which is higher than that of the other NiFe(CO3)(OH)(2) samples. Furthermore, the asymmetric supercapacitor with an optimized NiFe(CO3)(OH)(2) composite as the positive electrode and graphene as the negative electrode was used to illuminate a light emitting diode. These results confirmed the high performance of the NiFe(CO3)OH)(2) composite supercapacitor.