Elaboration and electrochemical characterization of two hydrogen storage alloy types: LaNi3 − xMnxCr2 (x = 0, 0.1, and 0.3) and La2Ni7

• Published in: Ionics 2018-07, Vol.24 (7), p.2017-2027
• Main Authors: Dhaouadi, H., Ajlani, H., Zormati, H., Abdellaoui, M.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Electrochemistry; Energy Storage; Optical and Electronic Materials; Original Paper; Renewable and Green Energy
• ISSN: 0947-7047; 1862-0760
• DOI: 10.1007/s11581-018-2441-6

The LaNi 3 −  x Mn x Cr 2 ( x  = 0.0, x  = 0.1, and x  = 0.3) intermetallic compounds were prepared by a high-energy ball milling process. XRD studies and Rietveld refinement indicated that the as-prepared alloys showed multi-phase structures: the main phases were LaNi 2 Cr 2 , LaNi 2.9 Cr 2 Mn 0.1 , and LaNi 2.7 Cr 2 Mn 0.3 ; and the two secondary phases: La 2 Ni 3 and residual Cr. The increase in the amount of Mn substituting Ni improves the reversibility and the kinetic absorption-desorption of the electrode’s electrochemical reaction and inhibits the cycling capacity degradation. The La 2 Ni 7 -type intermetallic compound is elaborated by mechanical alloying and investigated as a negative electrode material for nickel-metal hydride (Ni-MH) batteries. This study aims to optimize the milling time. The structural properties of the La 2 Ni 7 phases were determined by X-ray diffraction and quantified from the Rietveld refinement data. The hydrogen absorption/desorption properties are determined by electrochemical measurements using galvanostatic cycling process. Discharge capacities of La 2 Ni 7 alloys reached 438.58 mAh/g.