Structural stability of aluminum stabilized alpha nickel hydroxide as a positive electrode material for alkaline secondary batteries

Nanostructured, aluminum-stabilized nickel, hydroxides described as Ni 1− x Al x (OH) 2.(CO 3) x/2 · nH 2O ( x=0.05–0.2), which are similar to α-Ni(OH) 2· xH 2O in crystal structure are examined as cathode materials for Ni–Cd cells. The structure, morphology and electrochemical performance are investigated. The structural changes and stability of nanophase aluminum-stabilized, alpha nickel hydroxides with different x values analyzed during cycling by means of powder X-ray diffraction. Compared with β-Ni(OH) 2, the nanophase, aluminum-stabilized α-Ni(OH) 2 with x=0.15 is highly stable against overcharge.