Electrochemical energy storage application of MOF-derived porous NiO thin films synthesized by solvothermal route

Abstract

Metal oxides are the most suitable materials for supercapacitors because of their strong electrical characteristics and cheap prices. Owing to its large surface area, controlled pore structure, uniformity, the metal-organic frameworks are employed as inventive material for electrodes in the field of energy storage. In this report, Ni-MOFs have been prepared on conducting stainless steel substrates using a solvothermal technique with different Ni concentrations. Further, these films were annealed at 350 °C for getting NiO phase. The crystalline nature of MOF-derived NiO is confirmed by XRD. The surface morphology of the films has been studied with FE-SEM, showing a nanosheet-like structure. Consequently, electrochemical tests on NiO electrodes were performed in 1 M KOH with a potential window of -0.2–0.5 V. The NiO electrode deposited with 0.3 M concentration delivers a specific capacity of 680 C g−1 at a current density of 0.5 mA cm−2, an energy density of 22.40 Wh kg−1 at a power density of 2.4 kW kg−1 and good cyclic performance with 96% retention after 5000 cycles. The synthesized MOF derived NiO showed excellent specific capacity and good cycle stability due to their large surface area, porous and more durable structure. Hence, the synthesis approach designated here may provide an efficient way to develop MOF-derived NiO for effective supercapacitor applications.