Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Activation behavior of an AB(2) type metal hydride alloy for NiMH batteries
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
Show others and affiliations
Number of Authors: 52016 (English)In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 41, no 23, p. 9948-9953Article in journal (Refereed) Published
Abstract [en]

Activation behavior of an AB(2), namely (Ti0.36Zr0.64) (V0.15Ni0.58Mn0.20Cr0.07)(2) Laves phase alloy, was investigated with regards to; particle size, ball milling and hot alkaline treatments. Galvanostatic cycling in open cells showed that an untreated alloy initially had almost no capacity, but reached a value of 220 mAh/g after 14 cycles. Experiments with different particle sizes showed that coarse particles activate faster yielding an improved capacity. In terms of activation more pronounced effect was obtained with boiling the alloy powder in a hot KOH solution. A capacity in excess of 300 mAh/g is reached in the first cycle after a 20 min treatment. The capacity was highest after 80 min, yielding a value of 390 mAh/g well above that expected from the gas-phase storage in the alloy. This was attributed to the formation of rough surface in the powder, which may stabilize hydrogen bubbles allowing pressures above 1 atm to be reached locally in the surface.

Place, publisher, year, edition, pages
2016. Vol. 41, no 23, p. 9948-9953
Keywords [en]
Metal hydride, Laves phase, NiMH batteries, Activation, Particle size, Hot alkaline treatment
National Category
Chemical Sciences
Research subject
Inorganic Chemistry
Identifiers
URN: urn:nbn:se:su:diva-132398DOI: 10.1016/j.ijhydene.2016.03.196ISI: 000378359400031OAI: oai:DiVA.org:su-132398DiVA, id: diva2:952575
Conference
1st International Symposium on Materials for Energy Storage and Conversion (ESC-IS), Middle Eeast Technical University, Ankara, Turkey, September 07-09, 2015
Available from: 2016-08-15 Created: 2016-08-11 Last updated: 2018-04-04Bibliographically approved
In thesis
1. Development of metal hydride surface structures for high power NiMH batteries: Also extended cycle-life and lead to more effective recycling methods
Open this publication in new window or tab >>Development of metal hydride surface structures for high power NiMH batteries: Also extended cycle-life and lead to more effective recycling methods
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

By combining alkaline etching of hydrogen storage alloys or their hydrides with a controlled oxidation, it was possible to improve reaction kinetics and accelerate activation of MH-electrodes. Both AB5 and AB2 alloys were studied where A is mixtures of rare earth elements for AB5 alloys and titanium and/or vanadium, zirconium for AB2 alloys; nickel contributes the major part of B. With SEM and TEM studies the surface could be described as consisting of several phases where an interphase with active Ni-containing cluster protected the inner metallic hydrogen storage part of the powder particles. These catalytic Ni-clusters presumably lead to the fast activation and high discharge capacity of alloy.

This interphase was observed to be stable enough to allow us to develop a method, where we could add pure oxygen to a NiMH battery pack in order to regenerate the amount of electrolyte that was lost during long time cycling of the battery. Meanwhile, the method will rebalance the electrodes mitigating excessive pressures during over charge. Therefore, the internal resistance of cells can be reduced and cycle life will increase.

It was also shown that the stable interphase could survive a mild ball milling or sonication which enabled us to upcycle material from spent NiMH batteries into a better working MH-electrodes with improved kinetics and activation properties. Reuse of ball-milled or sonicated material could serve as a simple recycling alternative to energy-demanding metallurgical smelting methods and chemical consuming hydrometallurgical recycling processes, where the possibilities of up-scaling further favour the less complex mechanical treatments. The stable but catalytic interphase protecting the inner particles indicates that the MH-electrode material may perform better in its second life in a new NiMH battery.

Place, publisher, year, edition, pages
Stockholm: Department of Materials and Environmental Chemistry, Stockholm University, 2018. p. 44
Keywords
Metal hydrides, NiMH batteries, Surface treatment, Ni clusters, Rare earths hydroxides, Oxygen, Hydrogen
National Category
Inorganic Chemistry Materials Chemistry
Research subject
Inorganic Chemistry
Identifiers
urn:nbn:se:su:diva-154581 (URN)978-91-7797-218-1 (ISBN)978-91-7797-219-8 (ISBN)
Public defence
2018-12-10, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.

Available from: 2018-11-15 Created: 2018-04-03 Last updated: 2018-11-09Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full text

Search in DiVA

By author/editor
Shen, YangNoréus, Dag
By organisation
Department of Materials and Environmental Chemistry (MMK)
In the same journal
International journal of hydrogen energy
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 44 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf