【摘要】 采用均相沉淀法制备了不同Al含量的α-Ni(OH)2,用XRD和FT-IR对其结构进行了表征,用热重分析方法测试了其热稳定性。并用恒流充放电方法研究了不同Al含量取代样品的电化学性能。结果表明:用均相沉淀法,在Al的添加量为5%~20%(摩尔分数,下同)范围内均可制备得到稳定的α-Ni(OH)2;Al的添加量为0时,制备得到的样品为与α-Ni(OH)2相结构相同的碱式盐。ICP结果表明Al的添加量与产品中Al的实际含量之间有较大差别,且这种差别随Al的添加量的减小而增加。随着Al的添加量降低,样品中实际Al含量也降低,样品的放电比容量先升高,后降低;充电电压先降低后升高,而放电电压开始变化很小然后迅速下降。当Al的添加量为5%~20%时,样品经过50次循环后衍射峰向高衍射角方向偏移,但仍保持α-Ni(OH)2相结构。而Al的添加量为0时,经过50次循环后转化为α-Ni(OH)2,但α相结构受到很大破坏。更多还原

【Abstract】 In this paper, α-Ni(OH)2 with different Al contents was prepared by a homogeneous precipitation method. The microstructure was characterized by FT-IR and XRD, and the composition of the samples was analyzed with inductive coupled plasma (ICP). Galvanostatic charge-discharge, cyclic voltammetry and impedance spectroscopy were used to measure the electrochemical behavior of samples. Results show that the stable α-Ni(OH)2 phase can be obtained for the samples with Al contents in the range of 5wt%~20wt% by the homogeneous precipitation method. And the alkali salt with the same structure as α-Ni(OH)2 is obtained without Al addition. According to ICP, there is big difference between the Al contents in the practical solution and the addition, and this difference increases with the decrease of Al addition contents. The specific capacity of discharge increases first, then decreases with the Al contents decreasing, and the charge potential decreases first, then increases. The discharge potential changes little first, then decreases promptly. For the samples with Al contents in the range of 5wt%~20wt%, the diffraction peaks move towards high diffraction angle after cycled for 50 times. However, the α-Ni(OH)2 structure still remains. The sample without Al addition transforms into α-Ni(OH)2 after cycling 50 times and the structure is destroyed heavily.更多还原