Effect of Annealing Treatment on Gaseous Hydrogen Characteristics and Electrochemical Properties of La_0.67Mg_0.33Ni_2.5 Co_0.5 Alloy Electrodes

Abstract:

The effect of annealing treatment on the structure, gaseous hydrogen characteristics and electrochemical properties of the La _0.67 Mg _0.33 Ni _2.5 Co _0.5 alloys was investigated. Alloy structure analyses show that all of the alloys consisted of complex phases such as (La,Mg)₂(Ni,Co)₇ phase, (La,Mg)(Ni,Co)₃ phase and La(Ni,Co)₅ phase. The homogenization of composition was improved by annealing treatment. Gaseous hydrogen characteristics were also improved after annealing. The pulverization of the alloy particles was reduced after annealing treatment, which could improve the cycling stability. Electrochemical experiments show that all of the alloy electrodes exhibited good activation characteristics, that annealing treatment improved the maximum discharge capacities of the alloy electrodes from 371.1 mAh/g (as-cast) to 387.7 mAh/g (1173K). The cyclic stability of alloy electrodes was also improved after annealing. However, the high rate dischargeability characteristics were deteriorated.

• Periodical: Advanced Materials Research (Volumes 512-515)
• Pages: 1882-1887
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.512-515.1882
• Online since: May 2012
• Authors: Wei Na Zhang, Ping Li, Fu Qiang Zhai, Qi Wan, Li Qun Cui, Yun Long Li, Xuan Hui Qu
• Keywords: Alloy Structure, Electrochemical Property, Hydrogen Storage, Ni-MH Battery, Pulverization

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