Method for preparing ternary positive electrode material of high-performance lithium ion battery at low ammonia concentration

Abstract

The invention discloses a method for preparing a ternary positive electrode material of a high-performance lithium ion battery at low ammonia concentration, and belongs to the technical field of positive electrode materials of lithium ion batteries. The method comprises the following steps: dissolving salt containing nickel, cobalt and manganese in deionized water to prepare a mixed salt solution,adding a complexing agent into the mixed salt solution, adding acid to obtain a mixed solution; continuously pumping the mixed solution and the NaOH solution into a continuous coprecipitation reaction kettle filled with bottom liquid ammonia water respectively, enabling the total ammonia concentration of the reaction kettle to be the same as the concentration of the bottom liquid ammonia water inthe reaction process, continuously reacting to obtain a precursor material, grinding and mixing the precursor material and LiOH.H2O, and sintering to obtain the lithiated ternary material. The prepared NCM622 material is good in morphology, complete in crystal structure and uniform in element distribution, the material has high discharge capacity, good cycling stability and rate capability, and atotal battery matched with graphite and a Si / C negative electrode also has good electrochemical performance.

Description

technical field [0001] The invention belongs to the field of positive electrode materials for lithium ion batteries, and in particular relates to a method for preparing high-performance lithium ion battery ternary positive electrode materials under low ammonia concentration. Background technique [0002] Currently, lithium-ion batteries have become the most promising energy devices for portable electronic devices and electric vehicles due to their advantages such as high energy density and long cycle life. Among the many cathode materials used in lithium-ion batteries, ternary materials (LiNi x co y mn z o 2 , x+y+z=1) has attracted extensive attention due to its high reversible capacity, good safety and relatively low cost. The most commonly used and most excellent preparation method is to synthesize the precursor material by hydroxide co-precipitation-controlled crystallization method, and then obtain the finished material by lithiation roasting. [0003] Hydroxide co...

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Problems solved by technology

The ammonia concentrations used in these disclosed patents are all relatively high, which will produce a large amount of difficult-to-handle high-concentration ammonia-containing production wastewater, polluting the environment, and at the same time, a strong ammonia pungent smell is emitted in the air under high ammonia concentrations, and the factory production The harsh conditions are extremely harmful to the health of workers, so reducing the concentration of ammonia used and ammonia-free production have been extensively studied

However, the ternary material prepared only by reducing the ammonia concentration and the synergistic effect of pH value has a large particle size, a low tap density, and poor lithium storage performance.

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