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Updated: Feb 26, 2026
07:57
Author Spotlight: A Rapid, Microwave-Assisted Hydrothermal Synthesis Of Nickel Hydroxide Nanosheets
Published on: August 18, 2023
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Fluorine-Stabilized β-Nickel Hydroxides: Composition, Structural Features, and Electrochemical Properties
Helies Hyrondelle1,2, Jacob Olchowka1,3, Vincent Rodriguez4
1University Bordeaux, CNRS, Bordeaux INP, ICMCB, UMR 5026, F-33600 Pessac, France.
Inorganic Chemistry
|February 25, 2026
Summary
Fluorine incorporation into nickel hydroxide cathodes stabilizes structure but hinders electrochemical performance by preventing nickel oxidation. This research explores nickel hydroxyfluorides for improved battery stability.
Area of Science:
- Materials Science
- Electrochemistry
- Inorganic Chemistry
Background:
- Commercial alkaline batteries utilize nickel hydroxide cathodes, offering safety and cost benefits.
- Structural instability during cycling, due to phase transitions, limits battery lifespan.
- Stabilizing the beta-nickel hydroxide polymorph is crucial for enhancing battery performance.
Purpose of the Study:
- To synthesize and characterize fluorine-substituted nickel hydroxides (Ni(OH)2-xFx).
- To investigate the structural and electronic effects of fluorine incorporation.
- To evaluate the electrochemical performance and oxidation behavior of fluorinated nickel hydroxides.
Main Methods:
- Microwave-assisted hydrothermal synthesis of nickel hydroxyfluorides.
- Powder X-ray diffraction (PXRD) and vibrational spectroscopy (FTIR, Raman) for structural analysis.
- UV-vis-NIR spectroscopy for electronic properties and thermogravimetric analysis (TGA) for thermal stability.
- Galvanostatic cycling and chemical oxidation tests for electrochemical evaluation.
Main Results:
- Nickel hydroxyfluorides (Ni(OH)2-xFx) were synthesized with fluorine content up to x=0.48, maintaining the β-Ni(OH)2 structure.
- Fluorine incorporation increased lattice rigidity, altered O-H bond characteristics, and enhanced bond ionicity.
- Fluorinated samples exhibited higher decomposition temperatures and a novel route to nickel oxyfluorides.
- Electrochemical cycling showed significant capacity decrease, and oxidation tests revealed an inability to oxidize due to fluorine's high electronegativity.
Conclusions:
- Fluorine substitution in nickel hydroxide stabilizes the structure but impedes electrochemical activity by blocking nickel oxidation.
- Nickel hydroxyfluorides offer insights into structural stabilization mechanisms but are not suitable cathode materials in their current form.
- Further research is needed to balance structural stability with electrochemical functionality in nickel-based battery materials.
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