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A thorough study of all the steps involved in a typical industrial nickel hydroxide based active material preparation process has been carried out. The influence of the parameters involved in the reaction, graphite addition, sedimentation, washing, and homogenization steps upon the properties of the final product was determined. The results indicate that no significant particle growth takes place during the sedimentation step and it could thus be suppressed from the process, a fact that would result in cost and time savings. On the other hand, the sometimes disregarded final homogenization step turned out to be crucial in view of obtaining optimal electrochemical performances. Indeed, simple low cost additional milling treatments were found to significantly increase the electrochemical yields and are advisable for implementation in the industrial process.

The microstructural features of diverse samples are studied by powder X-ray diffraction using different methods for the analysis of the diffraction peak broadening. The results obtained are thoroughly analyzed taking into account the assumptions and simplifications done in each of the chosen methods (Scherrer, Williamson-Hall and Rietveld refinement) and direct observation of the studied specimens by transmission electron microscopy is used in order to contrast the results obtained. Classic simple methods that consider only size effects (Scherrer) or the combined effects of size and strains (Williamson-Hall) provide a rapid overview of the origins of line-broadening but the most reliable results are obtained when the whole diffraction pattern is taken into account (Rietveld refinement).Mater. Res. Soc. Symp. Proc. Vol. 972