Electrochemical study of nanostructured multiphase nickel hydroxide

摘要

The high density nano-crystalline multiphase nickel hydroxide containing at least three doping elements has been synthesized and its electrochemical characteristics studied. It was found that the structure of the material is a mixed phase of alpha-Ni(OH)(2) and beta-Ni(OH)(2). It was also found that they have a stabilized structure same as alpha-Ni(OH)(2) during long-term charge/discharge process. The electrochemical behavior of the high density spherical multiphase a-Ni(OH)2 was studied and found that they have much better redox reversibility, a much lower oxidation potential of Ni(II) than the corresponding oxidation state in the case of beta-Ni(OH)(2), and a much higher reduction potential. They exchange one electron during electrochemical reaction and have a higher proton diffusion coefficient. The mechanism of the electrode reaction is still found to be controlled by proton diffusion, and the proton diffusion coefficient is 5.67 x 10(-10) cm(2) s(-1). Moreover, they reveal a higher discharge capacity than beta-Ni(OH)(2)/beta-NiOOH because thin, exchange one-electron per nickel atom during charge/discharge process.