jp0655468_si_001.pdf (154.33 kB)
Phase Distribution and Electrochemical Properties of Al-Substituted Nickel Hydroxides
journal contribution
posted on 2007-03-29, 00:00 authored by L. J. Yang, X. P. Gao, Q. D. Wu, H. Y. Zhu, G. L. PanSubstituting small contents of aluminum for nickel in nickel hydroxides by a chemical coprecipitation and a
subsequent hydrothermal process can yield stable positive electrode materials. Detailed studies on the structural
evolution were conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission
electron microscopy (TEM). The electrochemical properties of Al-substituted nickel hydroxides in alkaline
solution were examined by charge−discharge experiments and cyclic voltammetric (CV) measurements.
Hydrothermal treatments improved the crystallinity of Al-substituted nickel hydroxides, which exhibited much
better electrode performance than the untreated samples. The sample with 10% (in mol) Al substitution having
a mixture structure with α- and β-phases after hydrothermal treatments showed the maximum discharge capacity
of 333 mAh/g, corresponding to 1.46 exchanged electrons per Ni atom in α-phase nickel hydroxides. The
phase distribution in the mixture has a great influence on the particle morphology, discharge capacity, potential
plateau, and redox potentials of nickel hydroxide electrodes.