Lithium iron phosphate-modified conductive carbon black composite electrode material preparation method

Abstract

The invention relates to the fields of energy storage technology and power battery material technology, and specifically relates to a lithium iron phosphate-modified conductive carbon black composite electrode material preparation method. The preparation method comprises (1) a step of subjecting common conductive carbon black to annealing treatment, and then performing oxidation treatment in a strong oxidant to prepare the modified conductive carbon black; and (2) a step of preparing the lithium iron phosphate-modified conductive carbon black composite electrode material. According to the invention, by addition of modified SP which is easily dispersed, the composite electrode material prepared by the invention has small specific surface, thus facilitating battery preparation.

Description

technical field The invention relates to the technical field of energy storage and power battery materials, in particular to a preparation method of a novel lithium iron phosphate-modified conductive carbon black composite electrode material with high capacity, excellent rate performance and high cycle stability. Background technique Electrode materials with electrochemical activity can be used in the production and manufacture of batteries. Among them, the positive electrode materials of lithium ion batteries include lithium cobalt oxide, lithium nickel oxide, spinel lithium manganate, ternary nickel cobalt lithium manganate, etc. Among them, lithium cobaltate is commonly used in small lithium-ion batteries, but the use of cobalt is expensive and unstable under high current and overcharge conditions, which is very unsafe; the crystal structure of lithium nickelate is less stable and safe, and manganese The cycle performance of lithium oxide is poor, especially under high te...

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Problems solved by technology

The use of organic pyrolysis products can obtain nanometer-level thickness and cover dense carbon sources, which can greatly improve the conductivity of the material, but the disadvantage is that the cracking products are not uniform, which easily leads to poor stability of the synthesized lithium iron phosphate batches; in addition The porous carbon produced by pyrolysis will lead to a large specific surface area of ​​the material, which is not conducive to the preparation of battery slurry; using inorganic carbon sources such as carbon black, conductive graphite, graphene, etc., because the amount of carbon source added can reach 10wt% of the synthetic product, so It can greatly improve the rate performance of the material, but the disadvantage is that the inorganic carbon source has poor hydrophilicity, it is difficult to disperse in polar solvent water, the distribution of carbon source is difficult to control, and the addition of too much carbon source will lead to a decrease in the specific capacity of the synthesized product

For this reason, in order to obtain lithium iron phosphate materials with high capacity, good rate performance and good cycle stability, the inventors chemically modified the inorganic carbon source to make it easy to disperse in the water solvent, so that adding a small amount of carbon source can Greatly improve the conductivity of the material, and there is no related report in the industry about similar practices

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