Characterization of Unusually Large “Pseudo-Single Crystal” of β-Nickel Hydroxide

Abstract

Unusually shaped and remarkably large, i.e., micrometric, “pseudo-single” crystals of β-nickel hydroxide are synthesized following the original route proposed by Scholder and Giesler in 1962. The so-obtained hydroxide is investigated and compared to the standard product made of polycrystalline spherical particles. Structural, morphological, vibrational and electrochemical properties are examined by X-ray diffraction, scanning electron microscopy, μ-Raman spectroscopy, and cyclic voltametry. Our study reveals that this “pseudo-single” crystal of β-nickel hydroxide is made of micrometric hexagonal plates constituted by extremely well ordered hexagonal nanocrystallites. This material shows high crystallinity and a “single crystal” type behavior in μ-Raman spectroscopy due to the coherent orientation of the nanocrystallites subunits. After a few tens of potentiodynamic cycles, this compound exhibits higher electrochemical capacity than the standard compound. These features make it a very promising candidate for use in rechargeable batteries.