The surface modified Ni(OH)₂ samples with Ni and Ni–cobalt (Ni–Co) layer, respectively, are prepared by an in-situ chemical reduction method using hydrazine hydrate as reductant and silver ion as activating agent. The samples are characterized by X-ray diffraction, energy dispersive spectroscopy, and scanning electron microscopy. As the Ni electrode cathode, the material is analyzed, and the electrochemical properties such as rate capability, cyclic voltammetry, and AC impedance are investigated. The results indicate that the metallization of the Ni(OH)₂ surface does not change the original morphologies and crystal structure of the sample. The in-situ reduced Ni–Co layer bonds tightly with the matrix, which increases the conductivity of Ni(OH)₂ particles, reduces the electrode polarization, lowers the charging voltage of the battery, and improves the reversibility of the electrode reaction of Ni(OH)₂. Moreover, it effectively increases the rate capability, energy density, and utilization rate of the active material of the Ni electrode.