Cathode Active Material Reuse Without Acid Leaching
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Solution Overview
Problem
Existing methods for recycling positive electrode active materials from lithium secondary batteries are not eco-friendly, require acid-based processes, fail to recover lithium, and do not effectively separate the active material from ceramic particles transferred during the manufacturing process, leading to degraded performance and increased costs.
Innovation Solution
A method involving heat treatment, washing with an alkaline lithium compound solution, and annealing to recover and reuse the positive electrode active material without dissolving it, while removing ceramic particles and maintaining electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If acid-based extraction methods are used to recover positive electrode active material, then active material elements can be extracted and reused, but the process becomes harmful to the environment and requires additional neutralization and wastewater treatment steps
Solution Approach 1:
The patent converts the harmful acid-based extraction process into a beneficial alkaline treatment process. By using an alkaline solution containing a lithium compound, the method achieves both the recovery of active material elements and the simultaneous recovery of lithium, while eliminating environmental harm. The alkaline treatment dissolves the ceramic particle coating and binds with fluorine-containing substances, transforming a potentially harmful process into an eco-friendly recovery method.
2Ease of manufacture
If ceramic particles are not removed from the positive electrode active material, then the recovery process is simpler, but the electrochemical performance of the recovered material is degraded
Solution Approach 1:
The patent introduces an alkaline solution containing a lithium compound as an intermediary medium to selectively remove ceramic particles while preserving the active material. The alkaline solution acts as a mediator that dissolves the ceramic particle coating through chemical reaction, binding with fluorine-containing substances in the ceramic particles. This intermediary treatment enables effective separation of ceramic particles from the active material, ensuring high electrochemical performance in the recovered material.
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 allows for eco-friendly recycling of positive electrode active materials with improved capacity and resistance characteristics, reducing processing costs and avoiding the use of hazardous solvents, while ensuring the recovered material can be reused directly in battery production.
Implementation Method 1
heat treating the separated positive electrode plate in the air or under oxygen atmosphere at 300-650°C to perform thermal decomposition of the binder and conductive material
Implementation Method 2
washing the recovered active material with an aqueous lithium compound solution showing alkalinity in an aqueous solution state
Implementation Method 3
adding a lithium precursor to the washed active material and carrying out annealing to obtain a reusable active material
Data Source
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AI summary
Disclosed is a method for reusing a positive electrode active material, including the steps of: dipping a stack cell including a stacked and integrated positive electrode plate, separator and negative electrode plate, in a polar solvent to separate the positive electrode plate; heat treating the separated positive electrode plate to perform thermal decomposition of the binder and conductive material in the positive electrode material layer of the positive electrode plate, separating the current collector of the positive electrode plate from the positive electrode active material layer and recovering the active material in the active material layer; washing the recovered active material with an aqueous lithium compound solution showing alkalinity in an aqueous solution state; and adding a lithium precursor to the washed active material and carrying out annealing to obtain a reusable active material.