Effect of reaction conditions on size and morphology of ultrasonically prepared Ni(OH)2 powders

Modern electrochemical devices require the morphological control of the active material. In this paper the synthesis of nickel hydroxide, as common active compound of such devices, is presented. The influence of ultrasound in the synthesis of nickel hydroxide from aqueous ammonia complexes is studied showing that ultrasound allows the fabrication of flower-like particles with sizes ranging in between 0.7 and 1.0 μm in contrast with the 6–8 μm particles obtained in the absence of ultrasound. The influence of gas flow, temperature of the process and surfactants in the ultrasonically prepared powders is discussed in term of shape, size and agglomeration of the particles. Adjusting the experimental condition, spherical or platelet-like particles are obtained with sizes ranging from 1.3 μm to 200 nm.

Research highlights
► Ultrasonic synthesis of small Ni(OH)2 particles from aqueous ammonia complexes.
► Spherical, flower-like or platelet-like morphologies depending on the experimental conditions.
► Shape and size dependence on temperature and gas flow.
► Prevention of agglomeration by dispersants additions to the reaction media.