Effect of synthesis temperature on the structural morphology of a metal-organic framework and the capacitor performance of derived cobalt-nickel layered double hydroxides

Three-dimensional interconnected nickel-cobalt layered double hydroxides (NiCo-LDHs) were prepared on nickel foam by ion exchange using a cobalt-based metal-organic framework (Co-MOF) as a template at different temperatures. The effects of the Co-MOF preparation temperature on the growth, mass, morphology, and electrochemical properties of the Co-MOF and derived NiCo-LDH samples were studied. The synthesis temperature from 30 to 50 degrees C gradually increased the mass of the active material and the thickness of the Co-MOF sheets grown on the nickel foam. The higher the temperature is, the larger the proportion of Co3+. beta-Cobalt hydroxide (beta-Co(OH)(2)) sheets were generated above 60 degrees C. The morphology and mass loading pattern of the derived flocculent layer clusters of NiCo-LDH were inherited from metal-organic frameworks (MOFs). The areal capacitance of NiCo-LDH shows an inverted U-shaped curve trend with increasing temperature. The electrode material synthesized at 50 degrees C had a tremendous specific capacitance of 7631 mF center dot cm(-2) at a current density of 2 mA center dot cm(-2). The asymmetric supercapacitor assembled with the sample and active carbon (AC) achieved an energy density of 55.0 Wh center dot kg(-1) at a power density of 800.0 W center dot kg(-1), demonstrating the great potential of the NiCo-LDH material for energy storage. This work presents a new strategy for designing and fabricating advanced green supercapacitor materials with large power and energy densities.