Solution combustion synthesis of lithium cobalt oxide - cathode material for lithium-ion batteries

Abstract

A simple but novel solution combustion synthesis (SCS) technique suitable for LiCoO 2 scale production was developed. Citric acid was used together with glycine to slow down the combustion rate; cobalt(II) nitrate was partially replaced with cobalt(II) carbonate hydroxide to reduce the heating of the off-gases using the excess heat of the redox reaction. As a result, no open flame or eruption of the powder product out of the reactor was observed; the rapid SCS process occurring in the desired non-turbulent mode is suitable for scaling. The influence of the ratios cobalt(II) nitrate/cobalt(II) carbonate hydroxide and glycine/citric acid on the LiCoO 2 powder product properties was examined along with the influence of the post-combustion annealing conditions and pH of the precursor solution. The thus-obtained LiCoO 2 powders were characterised by X-ray diffraction, scanning electron microscopy and particle size distribution analysis. Testing of the electrochemical behaviour of the LiCoO2 powders was performed in Li/LiCoO 2 test cells having 1M LiDFOB in EC/DMC (1:1, wt.) as an electrolyte. The results confirmed the high electrochemical activity of the SCS-derived LiCoO2powders; the best samples exhibited a discharge capacity ≥150 mAh g -1 and coulombic efficiency ≥99.5 % following 30 cycles at C/10 rate.