LFP Cathode Recycling via Fluidized Bed Impurity Removal
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Solution Overview
Problem
Current methods for recycling lithium iron phosphate batteries result in low-purity cathode materials due to mechanical crushing, which mixes aluminum and copper with the electrolyte, increasing recycling costs and affecting performance, limiting industrial application.
Innovation Solution
A method involving discharging, drying, and crushing waste lithium iron phosphate batteries, followed by a fluidized bed reaction with benzene sulfonate to remove carbon and fluorine, and subsequent acid and alkali treatments to separate impurities, with the addition of lithium and iron supplements for sintering, effectively reducing aluminum and copper content and improving cathode material purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical crushing is used to separate battery components, then separation efficiency is improved, but cathode material purity deteriorates due to mixing with aluminum and copper foils
Solution Approach 1:
The recycling process is divided into distinct stages: initial mechanical crushing for separation, followed by chemical treatment stages (acid leaching, alkali treatment) for purification. This segmentation allows each stage to optimize for its specific function without compromising overall purity
Solution Approach 2:
Chemical reagents (acid and alkali solutions) are introduced as intermediaries to separate and remove metal foil contaminants from the cathode material. These intermediaries selectively react with impurities while preserving the cathode material integrity
2Productivity
If high-temperature calcination is used for separation, then component separation is improved, but energy consumption increases
Solution Approach 1:
The process uses controlled chemical treatment parameters (acid concentration, temperature, time) to achieve separation at lower temperatures than traditional calcination. This parameter optimization reduces energy consumption while maintaining effective separation
3Device complexity
If aluminum and copper foils are mixed with electrolyte during crushing, then separation difficulty increases, but recycling cost increases
Solution Approach 1:
The process replaces continued mechanical separation attempts with chemical treatment methods. Acid leaching and alkali treatment chemically separate metal foils from the cathode material, avoiding the need for complex mechanical separation systems and reducing overall recycling costs
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves high-purity cathode materials with controlled recycling costs, resulting in batteries with improved performance and cycle stability, effectively addressing the limitations of existing recycling techniques.
Implementation Method 1
mixing the black powder obtained in step (1) with benzene sulfonate, and then reacting in a fluidized bed to obtain a black powder without carbon and fluorine removed
Implementation Method 2
adding acid into the black powder without carbon and fluorine removed in step (2) for solid-liquid separation to obtain a solution A and a solid A
Implementation Method 3
adding at least one of a lithium supplement agent, an iron supplement agent or phosphate to obtain a mixture, then adding a reducing agent into the mixture, and sintering to obtain a cathode material
Data Source
AI summary
A method for recycling and preparing a positive electrode material from waste lithium iron phosphate batteries. The method comprises the following steps: discharging, crushing, and stripping waste lithium iron phosphate batteries to obtain black powder; then mixing the black powder with benzenesulfonate, and reacting in a fluidized bed; and then adding an acid and an alkali to remove impurities, finally adding a lithium supplement, an iron supplement, or a phosphate, and a reducing agent, and sintering. According to the method, by controlling and optimizing the crushing, stripping, carbon and fluorine removal, and impurity removal processes, a positive electrode material with high purity can be recycled while controlling the recycling cost, and batteries prepared by means of the recycled positive electrode material have good performance.