High-density Al-substituted alpha-nickel hydroxide with interlayer NO3- for alkaline nickel-based rechargeable batteries has been synthesized using a polyacrylamide (PAM) assisted two-step drying method. In order to improve its electrochemical performance, Al-substituted alpha-Ni(OH)(2) with interlayer NO3- is modified by a simple anion exchange method using NaCl solution. The physical and electrochemical properties of the synthesized material are characterized by means of X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and a charge-discharge test. Compared with NO3- intercalated alpha-Ni(OH)(2) precursor, the resulting Cl- intercalated alpha-Ni(OH)(2) samples possess more excellent electrochemical activities, including higher proton diffuse coefficient, lower electrochemical impedance, higher specific capacity, and better cyclic stability. Especially, it is also found that the introduction of Cl- can greatly accelerate the activation process of alpha-Ni(OH)(2) electrodes. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.