Synthesis, Characterization and Electrochemical Behavior of Al/Yb/Co/Mn-Doped α-Ni(OH).

Multi-element-doped α-Ni(OH) was prepared by an ultrasonic-assisted co-precipitation method. The crystal structures and morphologies of the prepared samples were characterized by x-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The results showed that the interlayer spacings of all samples were larger than that of pure α-Ni(OH) and that the structural stability became better with increases in the number of doped elements and the doped ratio. The electrochemical performances of the prepared samples, including cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge tests, were also analyzed. The results indicated that Al/Yb/Co/Mn-doped α-Ni(OH) had better electrochemical reversibility, lower charge-transfer resistance, a larger proton diffusion coefficient (8.47 × 10 cm/s) and a higher discharge capacity (288.2 mAh g at 0.5 °C) than Al/Co/Mn-doped α-Ni(OH) due to the synergistic effect of the doped elements. [ABSTRACT FROM AUTHOR]