Positive Electrode Scrap Reuse Without Acidic Extraction
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Solution Overview
Problem
Current methods for recycling positive electrode active materials from lithium secondary batteries are not eco-friendly, as they involve acidic extraction processes that are costly and difficult to manage, and cannot effectively reuse all metal elements, particularly lithium, while also causing performance degradation due to particle cracking and chipping during the roll pressing process.
Innovation Solution
A method involving thermal treatment of positive electrode scrap to separate the active material layer from the current collector, followed by washing with a lithium compound solution, mixing with a lithium precursor, and spray drying to recover the active material, which is then annealed to restore its original properties without the need for acidic dissolution or additional chemical processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If acidic extraction processes are used to collect positive electrode active material, then the active material can be obtained, but the process becomes non-eco-friendly, costly, and requires additional neutralization and waste water treatment
Solution Approach 1:
The patent converts the harmful acidic extraction process into a beneficial thermal treatment process. Instead of using acids to dissolve and extract active materials, the invention uses heat to decompose the binder and separate the active material layer from the current collector, transforming a harmful chemical process into a beneficial physical-chemical process that avoids environmental contamination while achieving the same separation goal
Solution Approach 2:
The patent replaces the chemical extraction system (acids, dissolving, extracting) with a thermal-mechanical system (heating, decomposing, separating). The thermal treatment at elevated temperatures decomposes the binder material, allowing mechanical separation of the active material layer from the current collector, thereby eliminating the need for acidic chemical processes and their associated environmental hazards
2Manufacturing precision
If roll pressing is applied to positive electrode scrap, then the material can be compacted, but particle cracking and chipping occur which affects slurry properties and electrode performance
Solution Approach 1:
The patent applies thermal treatment to decompose the binder before any mechanical processing or compaction steps. This preliminary action weakens the binding forces holding particles together, allowing subsequent handling and processing to proceed without causing particle cracking or chipping, thereby preserving particle integrity while enabling efficient processing
Solution Approach 2:
The patent changes the physical-chemical parameters of the binder material through thermal treatment, transitioning it from a bound state to a decomposed state. This parameter change (temperature increase causing decomposition) fundamentally alters the mechanical properties of the electrode structure, making it more susceptible to gentle separation without particle damage
3Loss of substance
If existing recycling methods are used, then active material can be collected, but lithium and other key elements cannot be effectively collected and reused
Solution Approach 1:
The patent selectively extracts the active material layer from the current collector through thermal decomposition of the binder. This extraction process preserves the intact active material particles containing lithium and other metal elements, allowing for complete recovery and reuse of these valuable substances without the losses associated with acidic dissolution methods
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 allows for the eco-friendly reuse of positive electrode active materials without acidic processes, reduces waste, and maintains excellent resistance and capacity characteristics, while simplifying the recycling process and improving particle size distribution, thus enhancing the recyclability and performance of the reused materials.
Implementation Method 1
thermally treating positive electrode scrap comprising an active material layer on a current collector in air for thermal decomposition of a binder and a conductive material in the active material layer
Implementation Method 2
mixing the active material washed from the step (b-1) with a lithium precursor solution and spray drying
Implementation Method 3
annealing the active material spray dried from the step (b-2) to obtain a reusable active material
Data Source
AI summary
There is provided a method for collecting and reusing an active material from positive electrode scrap. The method for reusing a positive electrode active material of the present disclosure includes (a) thermally treating positive electrode scrap comprising an active material layer on a current collector in air for thermal decomposition of a binder and a conductive material in the active material layer, to separate the current collector from the active material layer, and collecting an active material in the active material layer, (b-1) washing the active material collected from the step (a) with a lithium compound solution which is basic in an aqueous solution, (b-2) mixing the active material washed from the step (b-1) with a lithium precursor aqueous solution and spray drying, and (c) annealing the active material spray dried from the step (b-2) to obtain a reusable active material.