纳米级复合氢氧化镍的循环伏安研究

Study on the Cyclic Voltammetry of Nanophase Nickel Hydroxide Composites

采用低温固相法和有机液相法制备氢氧化镍及化学掺杂金属阳离子的复合氢氧化镍 ,TEM测试表明合成出的样品均为纳米级复合氢氧化镍 ;循环伏安测试 ,发现样品还原峰电位值 (ER)与掺杂阳离子的电荷半径比 (z/r值 )呈现一定的关系 ,表现为电荷半径比越大 ,样品还原峰电位值也越大 .由此得出一个经验关系式 ,并且从晶体结构方面就还原峰电位值与掺杂金属阳离子的电荷半径比之间的关系以及聚乙二醇表面活性剂对掺杂样品的影响进行了探讨 .认为掺杂高价金属阳离子容易形成α 氢氧化镍 ,它是样品还原峰电位值增大的原因 .此外 。

Nanophase nickel hydroxide composites doped with several metal ions (such as Al3+, Zr3+, Co2+ and Zn2+) were prepared using low temperature solid-state reaction and organic liquid-phase reaction. The cyclic voltammetry experiments show that there is a certain relation between reduction peak potential (E-R) of the sample and the ratio of the doped ion charge (z) to radius (r), i.e. the larger the z/r value of doped metal ion, the more positive the reduction peak potential of the sample. An experimental formula can be summarized as: E-R1 - 1000(A(1)-A(2)) + 100sgn([100A(2)] - [100A(1)]) = E-R2. The dependence of E-R on z/r and the effect of surfactant PEG on samples were presented. Owing to the valence of the metal ions in the active material being high, nickel-based layered double hydroxides (Ni-NLDH) are prone to become isostructural alpha-nickel hydroxide, which causes the more positive reduction peak potential. Additionally, the reduction peak potentials of the samples are also affected by surfactant PEG coordinated to the doped metal ions.