Study of High Purity Cobalt Carbonate Nanocrystals Production by Microemulsion as Batteries Precursors

Abstract

The precipitation of cobalt carbonate nanocrystals was achieved through the reaction of a pure and rich solution of cobalt sulphate (Co 2+ : 16.80 g/l) with a solution of carbonate solution (200 g/l). A surfactant was added to the reacting mixture in order to control the shape and size of generated crystallites. Two parameters were then varied i.e. , the weight of surfactant agent and the precipitation time in accordance with Taguchi’s L4 full experimental procedure (2 2 ). Chemical and structural characterizations tests of the obtained precipitates were done through X-Rays Fluorescence (XRF), Scanning Electron Microscopy (SEM) and X-Rays Diffractometer (XRD); whereas the size of crystallites was assessed according to the Laue-Scherrer formula. The results obtained from the variance analysis (ANOVA) indicated an optimal size of cobalt carbonate’s crystallites of 13 nm with a cobalt content of 44.35% (equivalent to 89.45% of CoCO 3 ) at ambient temperature under the following conditions: pH = 7; Mixing speed: 800 tr/min; Surfactant weight: 8 g; and a mixing time: 10 minutes. SEM images revealed an agglomeration of the obtained nanocrystals due to suspected drying conditions i.e. , drying temperature and drying atmosphere. It is suggested that the experiment should be conducted under neutral conditions at a temperature below that of cobalt carbonate’s decomposition (181.41℃).