Electrochemical properties of nickel–aluminum layered double hydroxide/carbon composite fabricated by liquid phase deposition

Nickel–aluminum layered double hydroxide/carbon (Ni–Al LDH/C) composites have been fabricated using a mixed solution of {Al(NO3)3·9H2O and H3BO3} as fluoride scavengers in the liquid phase deposition (LPD) process. The amount of divalent Ni2+ substituted by trivalent Al3+ within the lattice of α-Ni(OH)2 was controlled by the concentration of Al(NO3)3·9H2O solution. X-ray diffraction studies reveal pure phase Ni–Al LDH, isostructural and isomorphic to α-Ni(OH)2 with higher interlayer distance. The electrochemical properties of the cathode materials containing 0, 8.6, 13.8, 17.8, 21.3 and 23.4 Al% were evaluated by the means of charge–discharge and cyclic voltammetry measurements. The overall comparison indicates that Ni–Al LDH/C composites have higher electrochemical performance than pure α-Ni(OH)2/C composite. The cathode with 17.8 Al% exhibits the best performance at 1 C compared to other Al3+ contents; a much lower voltage plateau, well separated from the oxygen evolution at the end of the charging as well as a single flat and high discharge plateau with a discharge capacity of 376.9 mAh gcomp−1. Short term durability test for 80 cycles showed that the electrode containing 13.8 Al% has the highest discharge rate at 2 C. The range of Al substitution 13.8–17.8 Al% provides a good electrochemical response.