Polycarboxylic acid hyper-dispersant for dispersing lithium iron phosphate precursor

Abstract

The invention discloses a preparation method of a polycarboxylic acid hyper-dispersant for dispersing lithium iron phosphate precursors, which comprises the following steps: firstly dissolving isoamylene alcohol polyoxyethylene ether in water, adding an oxidant solution, stirring uniformly; than dropwisely adding a mixed solution of a reducing agent and a chain transfer agent, and a comonomer solution respectively for polymerization; finally, adding an alkaline regulator for neutralization and curing so as to obtain the polycarboxylic acid hyper-dispersant for dispersing lithium iron phosphate precursors. Aiming at the characteristics that the system is weak acidic during the dispersion of lithium iron phosphate precursors and organic solvents such as ethanol and the like are used as a dispersing carrier, the hyper-dispersant prepared in the invention can effectively prevent electrode active materials in slurry from forming secondary aggregates, does not introduce impurity ions which are not contained in the precursors, thus ensures the mixing uniformity of the precursors, and further allows the preparation of lithium iron phosphate products with excellent performance.

Description

technical field [0001] The invention belongs to the field of battery materials, and in particular relates to a preparation method of a polycarboxylic acid-based hyperdispersant for dispersing lithium iron phosphate precursors in the preparation process of lithium battery cathode materials. Background technique [0002] Lithium iron phosphate (LiFePO4) has the advantages of good safety performance, relatively stable oxidation state, good cycle life, wide source of raw materials, cheap price, good high temperature resistance, high reversible charge specific capacity, non-toxic, non-polluting, etc. It is a new generation of Ideal cathode material for lithium-ion batteries. In-depth research on this type of material and actively promoting its industrialization are the key factors to solve the current lithium-ion batteries that are expensive, poor in safety, complicated in protection measures, and difficult to scale up. Its industrialization can not only make full use of my coun...

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Problems solved by technology

However, as the particle size becomes smaller and smaller, the electrode active materials in the slurry can easily form secondary aggregates during the mixing and dispersion process of the lithium battery slurry, which will cause serious agglomeration of the lithium battery slurry and affect the lithium battery slurry. Subsequent sintering quality

[0004] There is no hyperdispersant specially used for dispersing the lithium iron phosphate precursor. There are reports in the literature that cetyltrimethylammonium bromide is used as a dispersant, but adding cetyltrimethylammonium bromide will make the The content of bromide ions in the finished product increases, thereby contaminating the precursor, and a large amount of foam will be generated when the precursor is prepared

There are also literatures using polyacrylamide as a dispersant, but the dispersion effect of polyacrylamide is limited, especially since it is insoluble in organic solvents such as ethanol and acetone, there are great limitations in its use

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