Study of the Composition of a Precipitate Formed from Solutions for the Synthesis of Cathodic Materials Containing Manganese and Citric Acid

Cathode materials of lithium-ion batteries can be efficiently and quickly obtained by solution combustion synthesis (SCS) from nitrate solutions of d-elements and lithium in the presence of organic complexing agents such as glycine and citric acid. However, during the storage of weakly acidic nitric acid solutions of manganese, nickel, and cobalt, after the addition of glycine and citric acid, a pink precipitate forms, which violates the stoichiometry of the initial solution. Thermal and X-ray structural analysis, as well as chemical analysis to determine the carbon content, show that the precipitate is manganese citrate of the composition Mn(HC6H5O7)H2O. It is found that the composition of manganese citrate does not depend on the ratio of the amount of citric acid and metal nitrates in the working solution.