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Metal Hydride Battery Electrodes for High Current Density

高电流密度金属氢化物电池电极

基本信息

批准号：
04650621
负责人：
UCHIDA Hirohisa
金额：
$ 1.28万
依托单位：
Tokai University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

Recently, some types of Metal Hydride batteries have been commercialized. At present, there are still many material problems to be solved for manufacturing more improved Metal Hydride batteries which enable the rapid charge-discharge with high current densities. Many works point out the importance of substitutions of various elements for rare earths and Ni in the rare earth - Ni based alloys. However, the role of each substitutive elements in the electrodes is not well understood. This is mainly because of the complicated electrochemical reactions on the electrode surface which cannot be readily investigated.In this work, we tried to make an fundamental research to understand the roles of the cobalt substitution for Ni in hydriding kinetics of LaNi_5. Activation behaviors of LaNi_<2.5>Co_<2.5> alloys in hydrogen gas atmosphere and KOH solution were investigated. The samples surface were pretreated by heating in a 6N-KOH solution at 353 K for 3 hours.Co substitution shows an effective improvement in the initial activations, which may be explained by the formation of relatively stable oxidized surface. The LaNi_<2.5>Co_<2.5> alloy exhibits also no significant pulverization. The presence of cobalt may induce relatively high coherent oxide-metal interfaces which inhibits the generation of cracks in the cycling. After pretreatment of 6N-KOH solution at 353 K, LaNi_<2.5>Co_<2.5> alloy showed shortened incubation periods for both the initial activations and subsequent cyclic hydridings.

最近，一些类型的金属氢化物电池已经商业化。目前，要使更多的改进型金属氢化物电池能够在大电流密度下实现快速充放电，仍有许多实质性的问题需要解决。许多工作指出了稀土镍基合金中各种元素替代稀土和镍的重要性。然而，各取代元素在电极中的作用还不是很清楚。这主要是由于电极表面复杂的电化学反应不容易研究。在本工作中，我们试图对钴取代镍在LaNi5氢化动力学中的作用进行基础性研究。研究了LaNi2.5&lt；2.5&gt；Co&lt；2.5&gt；合金在氢气和KOH溶液中的活化行为。样品表面在353 K的6N-KOH溶液中加热3h后，Co的替代有效地改善了初始活化，这可能是由于形成了相对稳定的氧化表面所致。LaNi；2.5；Co；2.5&gt；合金也没有明显的粉化现象。钴的存在可能会诱导相对较高的共格氧化物-金属界面，从而抑制循环中裂纹的产生。经353K的6N-KOH溶液处理后，LaNi_lt；2.5&gt；Co_&lt；2.5&gt；合金的初始活化潜伏期和随后的循环氢化潜伏期均缩短。