• Temperature-induced control over phase selection among hydroxides of nickel

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      https://www.ias.ac.in/article/fulltext/boms/031/02/0169-0172

    • Keywords

       

      Nickel hydroxide; crystallinity; disorder; ammonia precipitation.

    • Abstract

       

      While at low (4°C) temperatures, addition of ammonia to aqueous metal nitrate solutions induces the precipitation of 𝛼-nickel hydroxide and at high (25–65°C) temperatures, 𝛽-Ni(OH)2 is formed. The crystallinity of the product improves at higher temperatures of precipitation and the product obtained at 65°C is devoid of various disorders such as stacking faults, turbostraticity and interstratification. This provides a simple and efficient alternative to the hydrothermal synthesis of crystalline 𝛽-Ni(OH)2. The temperature induced control over phase selection provides direct experimental evidence for the metastability of 𝛼-nickel hydroxide. Crystalline 𝛽-Ni(OH)2 is, however, a poor electrode material for alkaline secondary cells and exhibits a capacity of only 75 ± 10 mAh/g, against the theoretically expected 289 mAh/g.

    • Author Affiliations

       

      T N Ramesh1 P Vishnu Kamath1

      1. Department of Chemistry, Central College, Bangalore University, Bangalore 560 001, India
    • Dates

       
  • Bulletin of Materials Science | News

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