In situ investigation of commercial Ni(OH)(2) and LaNi5-based electrodes by neutron powder diffraction
Journal article, 2015

Electrochemical reactions at both positive and negative electrodes in a nickel metal hydride (Ni-MH) battery during charge have been investigated by in situ neutron powder diffraction. Commercially available beta-Ni(OH)(2) and LaNi5-based powders were used in this experiment as positive and negative electrodes, respectively. Exchange of hydrogen by deuterium for the beta-Ni(OH)(2) electrode was achieved by ex situ cycling of the cell prior to in situ measurements. Neutron diffraction data collected in situ show that the largest amount of deuterium contained at the positive electrode is de-intercalated from the electrode with no phase transformation involved up to similar to 100 mA h/g and, in addition, the 110 peak width for the positive electrode increases on charge. The negative electrode of composition MmNi(3.6)Al(0.4)Mn(0.3)Co(0.7), where Mm = Mischmetal, exhibits a phase transformation to an intermediate hydride gamma phase first and then to the beta phase on charge. Unit cell dimensions and phase fractions have been investigated by Rietveld refinement of the crystal structure.

Author

J. J. Biendicho

Stockholm University

Rutherford Appleton Laboratory

M. Roberts

Uppsala University

D. Noreus

Stockholm University

U. Lagerqvist

Nilar AB

R. I. Smith

Rutherford Appleton Laboratory

G. Svensson

Stockholm University

Stefan Norberg

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

Sten Eriksson

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

S. Hull

Rutherford Appleton Laboratory

Journal of Materials Research

0884-2914 (ISSN)

Vol. 30 3 407-416

Subject Categories

Materials Engineering

DOI

10.1557/jmr.2014.317

More information

Latest update

9/6/2018 1