Recycling method of retired lithium iron phosphate battery positive-electrode materials

Abstract

The invention discloses a recycling method of retired lithium iron phosphate battery positive-electrode materials. The method includes the steps: soaking and dissolving binding agents in an N-methylpyrrolidone solvent by the aid of the N-methylpyrrolidone solvent to strip LiFePO4 positive-electrode materials and aluminum foil fluid collectors; mixing the stripped waste LiFePO4 positive-electrode materials and binding agents; coating a carbon fabric or titanium mesh with mixture of the waste LiFePO4 positive-electrode materials and the binding agents to serve as a positive electrode; taking a graphite electrode as a negative electrode; building an electrolytic tank in electrolyte solution; driving lithium removal by the aid of a direct-current electric field to collectively recycle lithiumions and lithium removal product iron phosphate. According to the method, lithium removal is driven and adjusted by the direct-current electric field, lithium can be basically completely removed, subsequent treatment of the electrode materials after lithium removal is performed, so that treated electrode materials can be converted into the iron phosphate, and the iron phosphate can be used for preparing lithium iron phosphate positive-electrode materials and is good in electrochemical performance. The method is simple and convenient in operation process, controllable in condition, high in recycling rate and environmentally friendly, and popularization and application are facilitated.

Description

technical field [0001] The invention relates to a method for recycling positive electrode materials of waste batteries, in particular to a method for recycling positive electrode materials of decommissioned lithium iron phosphate batteries, and belongs to the field of recycling and recycling of lithium ion battery resources. Background technique [0002] Lithium-ion batteries (Lithium-ion batteries) have been widely used in smartphones, laptops, cameras, other electronic devices, and electric vehicles due to their advantages such as rechargeability and high energy density since they were put into commercial use in the 1990s. In recent years, with the widespread use of lithium-ion batteries in electronic equipment and vehicles, the number of corresponding scraps continues to increase. The electric vehicle industry is expected to generate significant demand for lithium-ion batteries. In the future, the lithium-ion battery waste stream will mainly come from electric vehicles. ...

AI Technical Summary

Problems solved by technology

Among them, LiCoO 2 The battery has excellent cycle performance and has been widely used. However, its development space is limited due to the scarcity of Co resources, high cost, high environmental pollution and poor anti-overcharge ability; LiMn 2 o 4 The battery is cheap, has high charge and discharge voltage, is environmentally friendly, and has excellent safety performance, but the cycle performance is poor due to the Jahn-Teller effect, and its electrochemical performance decays quickly due to the dissolution of manganese at high temperatures; LiFePO 4 Batteries are widely used in electric vehicles and other electric vehicles because of their advantages of low price, environmental protection, good safety performance and long cycle life. They are still the most promising cathode materials for lithium-ion batteries. It is foreseeable that lithium iron phosphate The substantial increase in the use of materials and the scale of production make recycling work of great significance, which is not only conducive to environmental protection, but also conducive to the sustainable use of resources

At present, there are two types of methods for recycling lithium iron phosphate electrode materials: solid-phase regeneration and wet recovery of metals. The solid-phase regeneration process is relatively simple, but the disadvantage is that the energy consumption is high, and iron, lithium, and phosphorus need to be replenished in proportion , and the wet process often needs to go through alkali leaching and acid leaching, and will produce a large amount of waste liquid to be treated, and there are many steps in the process

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