材料期刊网

球形氢氧化镍的微结构对氢镍电池(MH-Ni)镍电极的电化学性能有重要的影响.本文通过扫描电镜(SEM)和透射电镜(TEM)研究了用控制沉淀-结晶法制备的球形氢氧化镍的结构特征,并与传统非球形氢氧化镍进行了比较,同时讨论了球形氢氧化镍活性物质的电化学行为.研究结果表明,球形氢氧化镍粉体由微球颗粒组成,每一个微球由片状氢氧化镍叠砌而成,这种片状氢氧化镍晶粒又由约0.5nm厚的40层晶片组成,因而球形氢氧化镍是一种纳米结构材料.片状氢氧化镍晶粒在微球内基本上沿径向排列,晶粒之间相互连接形成三维网络结构,晶粒解理面之间存在许多孔隙或缝隙.这种结构在电池的充放电过程中具有良好的力学稳定性,微球内存在的孔隙或缝隙可以用作质子传递的通道而有利于缩短质子在固相中扩散的距离,从而降低电极极化和提高电极的电化学性能及使用寿命.

Microstructures of spherical Ni(OH)2 particles are significant to improve electrochemical performances for the nickel electrode in MH-Ni batteries. The structure of spherical Ni(OH)2 particles prepared by the controlled aqueous precipitation-crystallization process has been characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM)and was compared with the traditional Ni(OH)2 and the electrochemical behavior for the spherical Ni(OH)2 active materials was discussed in this article. The spherical nickel hydroxide materials consist of Ni(OH)2 microspheres, which characterize with a reticulate structure of platelet-like. In a spherical Ni(OH)2 particle there are full of pores, crannies between cleavages. The lattices in the crystalline Ni(OH)2 grains consist of about 40 layers with each layer approximately 0.5nm thick and the spherical nickel hydroxides are nano-structural materials. The crystalline grains in Ni(OH)2 spheres are radially arranged and intervein and these grains connect with each other to form a three-dimensional network-type structure. This structure is supposed to benefit the mechanical stability for the spherical particles during the charge/discharge processes and improve cycle life of the electrode.