Preparation method of lithium ion battery cathode material nano lithium iron phosphate

Abstract

The invention discloses a preparation method of a lithium ion battery cathode material nano lithium iron phosphate which belongs to the technical field of nano lithium iron phosphate preparation. The method comprises the following steps: preparing hydrous nano iron phosphate by a rotating packed bed method; roasting and dehydrating the hydrous nano iron phosphate to obtain anhydrous nano iron phosphate powder; weighing lithium source compound, carbon source compound and anhydrous nano iron phosphate according to a stoichiometric ratio, adding pure water and a dispersant, mixing and stirring the mixture uniformly, preparing a slurry, performing spray drying of the prepared slurry, performing heat treatment of the obtained powder with the protection of inert gas to obtain the nano lithium iron phosphate material. The nano lithium iron phosphate material prepared by the invention has uniform components and good batch stability, has specific discharge capacity at 1C rate of more than 130 mAh / g and specific discharge capacity at 5C rate of more than 110 mAh / g at room temperature, and has great application value in the power-type lithium ion battery field. The method is applicable to large-scale production, and has low cost.

Description

technical field [0001] The invention belongs to the technical field of preparing nano-lithium iron phosphate, and in particular relates to a preparation method of nano-lithium iron phosphate, a cathode material of a lithium ion battery. Background technique [0002] Lithium iron phosphate (LiFePO 4 ) is a new type of cathode material for lithium-ion batteries developed in recent years. The invention has the advantages of rich source of raw materials, low preparation cost, high specific capacity, good cycle performance, and little environmental pollution. At present, it has been widely used in a new generation of power or energy storage lithium-ion batteries. [0003] However, there are still deficiencies in its high-current charge and discharge performance, low-temperature performance, and volume specific energy. The high cost of battery manufacturing caused by the consistency problem also affects the large-scale application of battery packs. Therefore, it is necessary t...

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Problems solved by technology

Although the synthesis process of the high-temperature solid-phase method is simple, the reactants are not easy to mix uniformly, the reaction time is long, and multiple sintering is required. Most of the synthesized products have a particle size of microns, and the distribution is uneven, often containing impurities, and the shape is irregular. , the electrochemical properties of different batches of materials are quite different

This is because the solid phase method is difficult to accurately control the ratio of lithium, iron, and phosphorus, and the control of product purity, crystal morphology, and particle size is also very difficult, the stability of the product batch is poor, and the entire production process is long and energy consumption is high. Big

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