Recycling method of positive electrode material of lithium iron phosphate battery

Abstract

The invention relates to a method for recycling positive electrode materials of lithium iron phosphate batteries, comprising: ultrasonically washing the positive electrode waste pieces of the waste lithium iron phosphate batteries, filtering to obtain the active material of the pole piece; dissolving the active material of the pole piece in the first acid solution, Add an oxidizing agent, control the pH of the reaction solution at the end of the reaction to be 2.0-2.3, filter and separate to obtain the first filtrate to be recovered and ferrophosphorus slag; use lye to adjust the pH of the first filtrate to be recovered to be greater than or equal to 5, filter to remove the precipitate and then add Phosphate is reacted, and the pH of the reaction solution is controlled at the end of the reaction to be 10-11, the filtrate is filtered and dried, and lithium phosphate is recovered; the ferrophosphorus slag is dissolved in the second acid solution, and the complexing agent, Lithium hydroxide or lithium carbonate and carbon source are reacted, and colloidal precipitate is obtained by separation, crushed and roasted, and lithium iron phosphate is recovered. Through the above method, the recycling process is simplified, and the process is short and consumes less energy. The synthesized material has high compaction density and good electrical properties.

Description

technical field [0001] The invention relates to the technical field of recycling waste lithium iron phosphate batteries, in particular to a method for recycling positive electrode materials of lithium iron phosphate batteries. Background technique [0002] With the introduction of battery CTP technology and blade battery technology, the volume energy density of lithium iron phosphate has reached the level of ternary 111, and the cruising range of the car equipped with lithium iron phosphate has also reached more than 600km. With its advantages of high safety and low cost, the proportion of lithium iron phosphate in the passenger car market is increasing year by year. With the rapid growth of its market holdings, lithium iron phosphate batteries will inevitably be scrapped in 4-5 years, so it is urgent to develop a high-efficiency and low-cost closed-cycle process. [0003] First of all, there are two problems in the direct repair and reuse of lithium iron phosphate material...

AI Technical Summary

Problems solved by technology

[0003] First of all, there are two problems in the direct repair and reuse of lithium iron phosphate materials in waste lithium iron phosphate batteries: one is that after long-term circulation, the positive electrode material of waste batteries is lithium-deficient lithium iron phosphate

If the performance of the directly recycled product is too low, it cannot meet the requirements of the product

The second is that the positive electrode sheet contains more than 6% binder and conductive carbon. If it is used directly, the processing performance of the product is very poor, and the energy density is too low

The remaining ferrophosphorus slag is either directly used as waste or re-supplemented with iron or phosphorus to re-synthesize ferric phosphate. After that, the ferric phosphate is re-dried and dehydrated, and then added with lithium source for grinding, drying and roasting. The whole process is long and energy-consuming, and the recycling value is low. high

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