摘要
采用化学共沉淀法制备出不同含量Mg掺杂的氢氧化镍样品。应用X-射线衍射(XRD),傅里叶变换红外光谱(FTIR)和热重分析(TG)手段对样品的结构进行了表征,并用循环伏安法研究了样品的电化学性能。结果表明:与Mn、Al等元素掺杂到一定含量后使Ni(OH)2晶型由!型转化为"型不同,即使Mg掺杂含量达到30%,样品仍为#型。但样品晶格产生畸变,晶粒尺寸随Mg含量的增加先变小后增大,电化学性能随Mg含量的增加先变好后变坏。Mg最佳含量为5%左右,此时OH-数量增多,产生了大量的晶格畸变,c轴拉长,有利于质子扩散系数的变大,增强了反应的可逆性,提高了电极充电效率和活性物质的利用率,从而改善了电极的电化学性能。
The different amount of Mg-doping Ni （OH）2 samples were prepared by a coprecipitation method. The crystal structures were characterized by XRD, FTIR and TG methods. The electrochemical performances were also investigated by cyclic voltammetry method. The results show that even the Mg-doping content reaches 30%, the sample still is/3-phase, which is different from Mn-doping or AI-doping samples in which the samples are changed to e-phase from/3--phase when the doping amount reaches some levels. The distortion of crystal lattices are hap- pened. The size of crystalline grains diminishes and then increases, and the electrochemical performances also are better and then worse when the Mg-doping amounts increases. The suitable Mg-doping amount is about 5%. In this case, the number of OH- increases, the crystal lattice distortion is engendered, and the interlayer distance c is stretched, which are favorable to enhancement of the proton transfer between electrode materials. Therefore, the re- versibility of electrode reaction is improved, the charge efficiency is increased and the utilization of active materials is promoted, which results in improvement of electrochemical performance.
出处
《电源技术》
CAS
CSCD
北大核心
2007年第9期732-735,共4页
Chinese Journal of Power Sources
关键词
Mg
掺杂
氢氧化镍
相结构
电化学性能
Mg
doping
Ni（OH）2
phase structure
electrochemical performance
