Abstract：The accurate analysis of cobalt content has importance significance to control the electrochemical property of lithium-rich manganese-based cathode materials. Manganese has interference during the potentiometric titration of cobalt. Since the content of manganese in lithium-rich manganese-based cathode materials is high, the interference of manganese should be considered during the determination of cobalt by potentiometric titration. The sample was dissolved with hydrochloric acid and nitric acid. Potassium chlorate was added to oxidize manganese (II) into manganese dioxide precipitate, which was then filtrated for separation. The mixed solution of ammonium citrate-ammonium chloride-ammonia and the standard solution of potassium ferricyanide were added into the filtrate to completely oxidize cobalt. The excessive potassium ferricyanide was potentiometrically titrated with the standard titration solution of cobalt. Manganese dioxide together with the filter paper was nitrified with sulfuric acid and nitric acid. The residual cobalt in the precipitate was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). The sum of cobalt content determined by potentiometric titration and the residual content in the precipitate was the cobalt content in the sample. One actual sample and two synthetic samples of lithium-rich manganese-based cathode materials were determined according to the experimental method. The relative standard deviations (RSD, n=11) of determination results were between 0.26% and 0.33%. The experimental method was used to determine the actual samples of lithium-rich manganese-based cathode material, and the comparison test was carried out with ICP-AES. The results show that two methods were consistent.
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