稀土Nd~(3+)与Cu~(2+)掺杂非晶态纳米Ni(OH)_2材料的电化学性能

晶态氢氧化镍[Ni(OH)2]在碱性电解液中易发生相变,影响其电化学性能。文中采用微乳液快速冷冻共沉淀法制备Nd3+和Cu2+复合掺杂非晶态纳米Ni(OH)2粉体材料,并对其结构形貌及物理特性进行表征分析。结果表明,制备出的非晶态Ni(OH)2样品材料,微结构含有较多结晶水,物相近似球形,粒径大小在20—30nm。对样品电极材料的电化学性能测试发现,掺杂Nd3+和Cu2+的摩尔比为2∶1时,所制备的样品材料合成镍电极,并组装成MH-Ni模拟电池,在恒电流80mA/g下充电6h,40mA/g放电,终止电压为1.0V的充放电条件下,放电比容量高达348.0mA.h/g,放电中值电压为1.2723V,同时样品电极材料的氧化还原可逆性较好,电极过程的电化学阻抗较小。电化学性能优于目前MH-Ni生产应用的晶态β-Ni(OH)2电极材料。

Electrochemical performance of rare earth Nd~(3+) and Cu~(2+) -codoped material of amorphous nano-Ni(OH)_2

The crystalline nickel hydroxide is easily phase-changed in alkalescent electrolyte and its electrochemical performances are affected. The Nd~(3+) and Cu~(2+)-codoped material of amorphous nano-Ni(OH)_2 was prepared by the method of rapid freezing precipitation of micro-emulsion. The structure and physical characteristics of the samples were characterized. The results show that the sample powder synthesized by this method is amorphous, which contains a large amount of crystal water and its shape is similar to spherical shape with the average particle size of 20-30 nm. The electrochemical performances of this electrode material were also studied. When the mole ratio of Nd~(3+) to Cu~(2+) was 2∶ 1, the sample powder was prepared as the nickel electrode material, and then assembled into the MH-Ni simulation battery. Under the conditions that it is charged at 80 (mA/g) for 6 h and discharged at (40 mA/g) to the final voltage 1.0 V, the discharge specific capacity is as high as 348.0 mA·(h/g), and the middle discharge voltage is 1.272 3 V; the circle reversibility is good and the electrochemical impedance in the electrochemical reaction is small. The electrochemical performances of this samples are much better than those of (β-Ni(OH)_2) applied in MH-Ni production.