Regenerated Cathode Active Material with Low-Temperature Binder Removal
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Solution Overview
Problem
Existing methods for recycling cathode active materials in lithium secondary batteries are inefficient, leading to resource waste, environmental pollution, and high costs due to the use of acids and organic solvents, with issues such as gelation and non-uniform distribution causing discarded materials.
Innovation Solution
A method involving low-temperature heat treatment to remove solvents, followed by pulverization and further heat treatment to eliminate binders and conductive materials, with the addition of a lithium precursor and annealing to restore the cathode active material's structure, reducing residual lithium and improving thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional recycling methods using acids and organic solvents are employed, then cathode active material can be recovered, but environmental pollution and safety hazards (toxic gas generation, explosions) occur
Solution Approach 1:
The patent converts the harmful components (binder and conductive material) into beneficial removal targets through oxidative heat treatment. By heating the waste cathode composition at 300-650°C in an oxygen-containing atmosphere, the binder and conductive material are oxidized and removed, leaving pure cathode active material. This transforms the harmful mixture into a purification process that eliminates pollutants while recovering valuable materials.
Solution Approach 2:
The patent changes the temperature parameter to enable selective removal of components. By controlling the heat treatment temperature at 300-650°C, the process selectively oxidizes and removes binder and conductive material while preserving the cathode active material structure. This temperature parameter change enables environmental-friendly recycling without acids or organic solvents.
2Loss of substance
If waste cathode composition is not pulverized before heat treatment, then processing time is reduced, but binder and conductive material cannot be completely removed
Solution Approach 1:
The patent segments the waste cathode composition into fine particles through pulverization before heat treatment. This segmentation increases the surface area and ensures uniform contact between oxygen and all binder/conductive material components during heat treatment, enabling complete removal. The segmented particles allow thorough oxidation that would be impossible with intact composition.
Solution Approach 2:
The patent performs preliminary pulverization before the main heat treatment process. This preliminary action of grinding and size-reducing the waste composition ensures that subsequent heat treatment can efficiently and completely remove binder and conductive material. The preliminary size reduction is essential for achieving complete purification.
3Loss of substance
If high temperature heat treatment is used to remove binder and conductive material, then purification is improved, but cathode active material structure deteriorates
Solution Approach 1:
The patent optimizes the temperature parameter to 300-650°C, which is the critical range for selective oxidation of binder and conductive material while preserving cathode active material. This parameter change enables complete purification without structural deterioration, achieving the balance between purification and structure preservation.
Solution Approach 2:
The patent uses oxygen-containing atmosphere (air or pure oxygen) to accelerate the oxidation of binder and conductive material at moderate temperatures (300-650°C). This strong oxidizing environment enables complete removal of organic components without requiring high temperatures that would damage the cathode active material structure.
4Loss of substance
If lithium precursor is not added during annealing, then processing cost is reduced, but residual lithium remains high
Solution Approach 1:
The patent enables the cathode active material to self-regulate its lithium content during annealing by adding a lithium precursor. The precursor decomposes and releases lithium vapor that is automatically absorbed by the cathode active material structure, reducing residual lithium without requiring external lithium sources. This self-service mechanism reduces both cost and residual lithium.
Solution Approach 2:
The patent creates a composite system during annealing by combining cathode active material with lithium precursor (such as lithium carbonate or lithium hydroxide). This composite temporarily forms during processing, enabling lithium redistribution and reduction of residual lithium content, then the precursor decomposes leaving pure cathode active material with optimized lithium content.
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 recycles cathode active materials with excellent thermal stability and reduced residual lithium, enhancing initial capacity and lifespan while being environmentally friendly and cost-effective by avoiding acids and organic solvents, thus preventing toxic gas generation and explosions.
Implementation Method 1
heat-treating a waste cathode composition containing a cathode active material, a conductive material, a binder, and a solvent at low temperature to remove the solvent
Implementation Method 2
heat-treating the powdered waste cathode composition at 300 to 650 °C to remove the binder and the conductive material
Implementation Method 3
washing the annealed cathode active material with a washing solution
Data Source
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AI summary
The present invention relates to a method of recycling a cathode active material and a recycled cathode active material prepared using the same. More particularly, the present invention relates to a method of recycling a cathode active material, the method including step (a) of heat-treating a waste cathode composition containing a cathode active material, a conductive material, a binder, and a solvent to remove the solvent; step (b) of pulverizing the waste cathode composition from which the solvent has been removed; step (c) of heat-treating the powdered waste cathode composition at 300 to 650 °C to remove the binder and the conductive material and recover the cathode active material; step (d) of adding a lithium precursor to the recovered cathode active material and performing annealing at 400 to 1000 °C; and step (e) of washing the annealed cathode active material with a washing solution and a recycled cathode active material prepared using the same. The present invention has an effect of providing a method of recycling a cathode active material and the recycled cathode active material prepared using the same. According to the present invention, by heat-treating a waste cathode composition containing a cathode active material, a conductive material, a binder, and a solvent at low temperature to remove the solvent, pulverizing the waste cathode composition, and then performing heat treatment, the binder and the conductive material may be completely removed, the structure thereof may be restored to that of a fresh cathode active material, thermal stability may be excellent, the amount of residual lithium may be reduced, and the initial capacity and lifespan characteristics of a secondary battery may be excellent.