Fabrication of binary transition metal hydroxides and their nanocomposite with CNTs for electrochemical capacitor applications

In this paper, we have prepared the flower-like nanoarchitecture of the Ni-Co binary metal layered hydroxides (Ni-Co-BMLHs) by urea assisted Solvothermal process and formed their nanocomposite with 5% CNTs via ultra-sonication approach. The physical characterizations of the prepared samples were carried out to obtain the compositional, structural, and morphological information. The influence of CNTs (5%) on the electronic conductivity of the nanocomposite was examined by current-voltage (I-V) experiments. In nanocomposite, the effective interaction between the Ni-Co-BMLHs and CNTs results showed good electrical conductivity (1.52 x 10(-2) S/m) that further facilitates the charge-transportation process during the electrochemical reactions. From electrochemical tests, the Ni-Co-BMLHs/CNTs based electrode showed excellent electrochemical activity with a specific capacitance (Cs) of 1305 F/g at 1 A/g. After 3000 CV cycles, the nanocomposite based electrode lossed 10.43% of its initial Cs, which reveals its desireable capacity retention. Moreover, the nanocomposite also exhibits superior rate capability as it lost just 8% capacitance by doubling the current density. The lower charge transfer resistance (Rct, 2.53 Omega) of the Ni-Co-BMLHs/CNTs than that of pure Ni-Co BMLH (3.92 Omega) during the EIS measurements also indicate that the CNTs additive in the nanocomposite lowers the internal resistance that facile electron transport during the faradaic reactions. The obtained results present the Ni-Co BMLHs/CNTs as unique electrode materials that have the potential for high-performance supercapacitors.