Positive Electrode Material Recycling Without Acid Leaching
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Solution Overview
Problem
Current methods for recycling positive electrode active materials from lithium secondary batteries face challenges such as environmental pollution, high costs, loss of functional coating layers, and risks of toxic gas generation, due to the use of acids and organic solvents, which affect the rate performance and sustainability of the recycling process.
Innovation Solution
A method involving heat treatment of waste positive electrodes with water containing ionic solid salts to remove residual F components, followed by annealing with lithium precursors, which recovers the positive electrode active material without decomposing it, thereby improving rate performance, reducing environmental impact, and eliminating the need for acid-based processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acid dissolution method is used to extract rare metals, then metal extraction efficiency is improved, but environmental pollution and process cost increase due to neutralization and wastewater treatment requirements
Solution Approach 1:
The patent converts the harmful acid dissolution process into a beneficial direct recycling process by using alkaline treatment to remove the functional coating layer selectively, transforming an environmentally harmful method into an eco-friendly process that maintains metal element integrity while achieving effective separation
Solution Approach 2:
The patent replaces the chemical acid dissolution system with a mechanical/physical alkaline treatment system that uses controlled chemical reactions under specific conditions (temperature, concentration, time) to achieve separation without the harmful effects of strong acid dissolution, eliminating the need for neutralization and wastewater treatment
2Ease of manufacture
If functional coating layer is removed during recycling, then binder removal is improved, but rate performance deteriorates due to loss of F compound layer
Solution Approach 1:
The patent applies local quality by selectively removing only the functional coating layer (F compound layer) while preserving the underlying positive electrode active material structure. The controlled alkaline treatment targets specific regions (the coating layer) without damaging the bulk material, maintaining rate performance while achieving binder removal
Solution Approach 2:
The patent uses parameter changes by controlling treatment conditions (alkaline solution concentration, temperature, treatment time) to achieve selective removal of the functional coating layer. By optimizing these parameters, the process removes the coating layer effectively while preserving the rate performance characteristics of the underlying active material
3Device complexity
If simple washing is used to remove binder, then process complexity is reduced, but functional coating layer is lost due to excessive washing water requirement
Solution Approach 1:
The patent converts the harmful effect of washing water (which causes coating layer loss) into a beneficial selective removal process. By using alkaline treatment instead of water washing, the process achieves binder removal while actually preserving the functional coating layer, turning a potentially harmful process into a protective one
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
This method enhances the rate performance of recycled positive electrode active materials, minimizes the loss of functional coating layers, and allows for eco-friendly recycling without toxic gas generation, making it suitable for mass production while maintaining metal element integrity.
Implementation Method 1
washing the recovered positive electrode active material with water containing an ionic solid salt
Implementation Method 2
step A of recovering a positive electrode active material by heat-treating a waste positive electrode including a current collector and a positive electrode active material layer coated thereon at 300 to 650° C. in air
Implementation Method 3
step C of adding a lithium precursor to the washed positive electrode active material and performing annealing at 400 to 1,000° C. in air
Data Source
AI summary
A method of recycling a positive electrode active material and a recycled positive electrode active material prepared by the method. The method includes the steps of recovering a positive electrode active material by heat-treating a waste positive electrode comprising a current collector and a positive electrode active material layer coated thereon at 300 to 650° C. in air, washing the recovered positive electrode active material with water containing an ionic solid salt, and adding a lithium precursor to the washed recovered positive electrode active material and performing annealing at 400 to 1,000° C. in air.