In-situ immobilization cobalt-based metal-organic frameworks nanosheets on carbon composites for supercapacitors

The Ni-alanine complex was calcined under a high-temperature nitrogen environment after being synthesized at room temperature. The Ni/C precursors carrying nickel nanoparticles were obtained. A series of composites with different times of stirring (CoMOF@Ni/C) were prepared by in-situ growth of CoMOF on Ni/C precursors. Various electrochemical measurement technologies helps us analyze the potential of CoMOF@Ni/C composites for supercapacitors. Thereinto, CoMOF@Ni/C with a stirring duration of 12 h (denoted as F-12) reached a maximal specific capacitance of 27.73 mAh g-1, and an 84.1 % coulombic efficiency. Meanwhile, the F-12//AC aqueous device was created with a cycling feature that only showed 8 % decay. This method of MOFs in situ immobilization not only prevents the excessive aggregation of Ni nanoparticles in the Ni/C precursor, but also provides more electrolyte contact area. Therefore, mass transfer and electron transfer can be facilitated throughout the electrochemical process. Simultaneously, the stability and conductivity of carbon substrates obtained from the calcination in a nitrogen atmosphere could effectively make up for the shortage of pure MOFs.