Comparison on structure and electrochemical performances of NiAl-LDH, CoAl-LDH and NiCoAl-LDH

Abstract

NiAl, CoAl and NiCoAl hydroxides were fabricated via urea decomposition method. The structure and morphology of samples were characterized by X-Ray diffraction, FTIR, scanning electron microscope, X-ray photoelectron spectroscope, and nitrogen adsorption desorption. The results indicate that three samples exhibit hydrotalcite structure and different morphology. Specific surface area of NiCoAl is the smallest among the three samples. Ni and Co elements coexist in the form of bivalent in NiCoAl-LDH. Cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and AC impedance tests demonstrate that, at the current density of 0.6 A/g, specific capacitance of NiAl, CoAl and NiCoAl electrodes is 468, 507 and 929 F/g, respectively. The capacitance retention of their electrodes is 30%, 36% and 40%, respectively, after 3000 cycles at the current density of 6 A/g. Based on these properties, NiCoAl is superior in electrochemical performance to the others.