Solvothermal synthesis of Ni/Co-based metal-organic framework with nanosheets-like structure for high-performance supercapacitor

In the present investigation, we have successfully synthesized Ni/Co-based metal-organic framework thin films on stainless steel substrates via facile and low-cost solvothermal method using 1,4-benzenedicarboxylic acid as an organic linker. X-ray diffraction technique (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), and electrochemical studies have been used to characterize the Ni/Co-MOF electrode materials. The purity and crystallinity of Ni/Co-MOF thin films were studied with the help of XRD. FESEM images showed that Ni/Co-MOF thin films have a nanosheets-like morphology which is suitable for supercapacitor applications. The functional groups present in the sample were confirmed by Fourier Transform Infrared Spectroscopy. The electrochemical performance of Ni/Co-MOF coated stainless steel was studied in 1 M KOH electrolyte at various scan rates and current densities. The NiCo2-MOF material provides a specific capacitance of 1070 Fg- 1 at the current density of 0.5 mA cm- 2. Additionally, the NiCo2-MOF electrode exhibits an excellent energy density of 30.96 Wh kg- 1 at a power density of 3.2 kW kg- 1 and outstanding cyclic stability with 85 % retention after 5000 charge/discharge cycles. The results suggest that NiCo2-MOF 2-MOF offers excellent electrochemical performance and may be a potential candidate for supercapacitor application.