【摘要】 为了改善La-Mg-Ni-Co系贮氢电极合金的综合电化学性能,研究了退火处理对La0.7Mg0.3(Ni0.85Co0.15)3.4相结构和电化学性能的影响.在1073~1223 K下退火9h制得样品,并进行了XRD分析以及恒电流充放电、线性极化和恒电位阶跃3种电化学测试.结果表明,铸态和退火态合金均由具有PuNi3结构的主相及少量杂相组成.退火态合金相的成分和结构均匀性得到明显改善,并具有较低的吸氢体积膨胀率.退火处理使合金的最大放电容量有所提高,循环稳定性得到明显改善.退火态合金放电容量的提高与合金中主相丰度的增大密切相关.合金循环稳定性的改善主要归结于退火态合金具有较低的吸氢体积膨胀率和较好的合金成分均匀性.更多还原

【Abstract】 To improve the overall electhochemical properties of La-Mg-Ni-Co based hydrogen storage electrode alloys,the influences of annealing treatment on the phase structure and electrochemical properties of La0.7Mg0.3(Ni0.85Co0.15)3.4 were investigated.When the samples were annealed at 1 073～1 223 K for 9 h,XRD analyse and 3 electrochemical tests including galvanostatic charge-discharge,linear polarization and potentialstatic discharge were performed.Results show that the as-cast and annealed alloys consist of a main phase with PuNi3-type structure and a few impurity phases,but that the annealed alloys have the obviously improved homogeneity of component and structure,and have a noticeable low cell volume expansion rate on hydriding.The anneal treatment increases the maximum discharge capacity and the cyclic stability.The increasing discharge capacity of the annealed alloys is closely related to the increasing abundance of main phase in the alloys.The cyclic stability improvement of the annealed alloys is mainly ascribed to lower volume expansion on hydriding and makes more uniform composition.更多还原