Preparation method of nickel-cobalt-manganese ternary precursor seed crystal

Abstract

The invention discloses a preparation method of a nickel-cobalt-manganese ternary precursor seed crystal. The preparation method comprises the following steps: preparing a nickel-cobalt-manganese mixed salt solution, liquid caustic soda and an ammonia water solution; preparing a reaction base solution in a reaction kettle, and introducing N2; continuously introducing the nickel-cobalt-manganese mixed salt solution, the caustic soda liquid and the ammonia water solution into the reaction kettle respectively, and carrying out coprecipitation reaction; starting to overflow when the particle size D50 of the slurry generated by the coprecipitation reaction is 90-95% of the target particle size, stopping introducing N2 at the moment, and introducing oxygen into the residual slurry in the reaction kettle to oxidize Mn<2+> in the slurry into Mn<4+>; and stopping introducing oxygen when the slurry D00 in the reaction kettle is less than 1.0 mu m and the span d is greater than or equal to 0.9 to obtain the nickel-cobalt-manganese ternary precursor seed crystal. According to the method, Mn<2+> in the feed liquid is oxidized into Mn<4+> with smaller solubility product, the operation is simple, the pH value in the reaction process is stable, the balance between crystal nucleation and growth is easy to control, the particle size distribution fluctuation is small, and the morphology consistency of precursor particles is good.

Description

technical field [0001] The invention relates to the field of preparation of new energy battery material precursors, in particular to a method for preparing nickel-cobalt-manganese ternary precursor crystal seeds. Background technique [0002] The nickel-cobalt-manganese ternary precursor is the most important raw material for the preparation of lithium-ion battery cathode materials, and the main preparation method of the ternary precursor is to add nickel-cobalt-manganese metal salt solution, liquid caustic soda, and ammonia water into the reactor at the same time for co-precipitation reaction. In the process of preparing the ternary precursor by the continuous method (feeding while feeding), the particle size and distribution of the target precursor are generally prepared by controlling the reaction balance by adjusting the pH value of the reactor slurry, ammonia concentration, and ternary flow rate. The change of pH value is achieved by adding liquid caustic soda in a cert...

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Problems solved by technology

[0002] The nickel-cobalt-manganese ternary precursor is the most important raw material for the preparation of lithium-ion battery cathode materials, and the main preparation method of the ternary precursor is to add nickel-cobalt-manganese metal salt solution, liquid caustic soda, and ammonia water into the reactor at the same time for co-precipitation reaction. In the process of preparing the ternary precursor by the continuous method (feeding while feeding), the particle size and distribution of the target precursor are generally prepared by controlling the reaction balance by adjusting the pH value of the reactor slurry, ammonia concentration, and ternary flow rate. The change of pH value is achieved by adding liquid caustic soda in a certain period of time. If the pH adjustment range is small and the seed crystals cannot be formed excessively, the precursor particles in the reactor will always agglomerate and grow, and the particle size distribution is too narrow to meet the requirements. Requirements, if the pH adjustment range is too large, it may cause explosive generation of seed crystals in a short period of time, which will seriously damage the reaction balance and lead to material scrapping. In addition, pH cycle fluctuations will also affect the crystallization of the primary particles of the precursor, resulting in secondary particles of the precursor The shape of the difference is large