High-temperature electrochemical performance of low-cost La–Ni–Fe based hydrogen storage alloys with different preparation methods
- Department of Advanced Energy Materials, College of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China)
- Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065 (China)
Highlights: • Effects of four different preparation processes were studied at 20/60 °C. • All NS + HT, RS and RS + HT processes can optimize the thermodynamic performance. • The HT process can provoke the precipitation of A{sub 2}B{sub 7} and leads to a poor cycling life. • Al exhibits the most remarkable dissolution for all the alloys, especially at 60 °C. - Abstract: In order to optimize the microstructure and high temperature electrochemical performances of low-cost AB{sub 5}-type Ml(NiMnAl){sub 4.2}Co{sub 0.3}Fe{sub 0.5} hydrogen storage electrode alloys, four different preparation methods including normal solidification (NS), normal solidification and 900 °C heat treatment (NS + HT), rapid solidification (RS), rapid solidification and 900 °C heat treatment (RS + HT) were adopted in this work. All alloys exhibit CaCu{sub 5} type hexagonal structure and there is a small amount of A{sub 2}B{sub 7} phase in NS + HT and RS + HT alloys. It is found the using of HT process can decrease the hydrogen equilibrium plateau pressure, the plateau slope and hysteresis at 40, 60 and 80 °C. The NS + HT and RS + HT alloys also possess better activation, high rate discharge performance, larger discharge capacity, but poor cycling performance due to the existence of A{sub 2}B{sub 7} phase which can accelerate dissolution of Ni, Mn and Fe elements in KOH alkaline electrolyte. The RS process can make alloy exhibit the best cycling performance especially at 60 °C.
- OSTI ID:
- 22581482
- Journal Information:
- Materials Research Bulletin, Vol. 76; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM ALLOYS
COBALT ADDITIONS
ELECTROCHEMISTRY
HEAT TREATMENTS
HEXAGONAL LATTICES
HYDROGEN
HYDROGEN STORAGE
HYSTERESIS
IRON ADDITIONS
MANGANESE ALLOYS
MICROSTRUCTURE
NICKEL ALLOYS
PERFORMANCE
POTASSIUM HYDROXIDES
SOLIDIFICATION
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES