Insights into the electrochemistry of (CoxNi(1−x))2Al-NO3 Layered Double Hydroxides

A series of (CoxNi1−x)2Al-NO3 (0 ≤ x ≤ 1) Layered Double Hydroxides (LDH) has been synthesized by the coprecipitation method. Their chemistry, structure and morphology were characterized using Inductively Coupled Plasma Atomic Emission and Energy-Dispersive X-ray Spectroscopies, Powder X-Ray Diffraction, Fourier Transformed Infrared spectroscopy, Raman spectroscopy and Scanning Electron Microscopy. The electrochemical behaviors of the LDH were investigated by Cyclic Voltammetry, Electrochemical Impedance Spectroscopy and Galvanostatic Charge/discharge with Potential Limitation measurements. The relationship between chemical composition of the LDH compounds (i.e. substituted samples vs physical mixtures) and their electrochemical properties is discussed. Special attention was paid to i) the role of the electrolyte cation (0.1 M COH, C+ = K+, Li+ and Na+) and to ii) the contribution of (CoxNi1−x)2Al-NO3@graphene nanocomposites (x = 0, 0.5, 1) in improving electron transfer in the materials.