Spherical Al-substituted gamma-NiOOH as an individual positive electrode material for a new type of alkaline primary/rechargeable Zn-NiOOH battery was prepared by the chemical oxidation of spherical Al-substituted alpha-Ni(OH)(2). The spherical Al-substituted gamma-NiOOH was characterized by XRD, SEM, Fr-IR, TGA-DTG, TPD-MS and HT-XRD. The tap density and average nickel oxidation state were measured. Its electrochemical performance and storage stability were also investigated. The results show that the as-prepared spherical Al-substituted gamma-NiOOH has remarkably higher specific discharge capacity and superior storage stability in alkaline electrolyte compared to spherical beta-NiOOH. (c) 2006 Published by Elsevier Ltd.