Recycled Cathode Microstructure Tuning via Leach Impurity Control
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Solution Overview
Problem
Conventional recycling processes for Lithium-ion batteries, particularly for NMC charge materials, often result in cathode materials with undetermined and unfavorable microstructures such as internal voids and porosity, making it difficult to meet customer specifications for performance and physical characteristics when substantial quantities are recycled.
Innovation Solution
A method is introduced that involves selective leaching of charge material metals followed by impurity control in the recycling leach solution to adjust the concentration of soluble ions, which affects the microstructure of the cathode material precursor, allowing for the formation of targeted microfeatures and microstructures through co-precipitation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional recycling processes are used for NMC charge materials, then recycling efficiency is improved, but the microstructure of cathode material becomes undetermined and unfavorable
Solution Approach 1:
The patent applies parameter changes by adjusting the concentration of soluble ions (such as lithium, sodium, potassium) in the leach solution to specific ranges. This controlled modification of chemical parameters during the leaching process enables precise control over the microstructure formation during co-precipitation, resolving the contradiction between recycling efficiency and microstructure control.
Solution Approach 2:
The patent uses soluble ion impurities as templates or copying agents that guide the formation of desired microstructures during co-precipitation. These ions are incorporated into the cathode material precursor particles, creating internal voids and controlling pore volume that replicate target microstructural features, thereby achieving deterministic microstructure control in recycled materials.
2Manufacturing precision
If soluble ion impurities are removed during leaching, then purity is improved, but microstructure formation is adversely affected
Solution Approach 1:
The patent converts the harmful effect of soluble ion impurities into a beneficial process feature. Instead of removing these ions as conventional processes would, the method retains and controls their concentration to drive the formation of desired microstructures. The impurities become essential for creating internal voids and controlling porosity, transforming a quality defect into a process advantage.
3Ease of manufacture
If co-precipitation is performed without soluble ion control, then process simplicity is maintained, but particle microstructure becomes unfavorable
Solution Approach 1:
The patent applies preliminary action by adjusting the soluble ion concentration in the leach solution before the co-precipitation step. This pre-conditioning of the solution ensures that when co-precipitation occurs, the desired microstructure forms automatically without requiring additional process steps during or after precipitation, maintaining simplicity while achieving precision.
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 approach enables the production of recycled cathode materials with desired microstructures, improving their performance and physical characteristics, such as pore volume and surface area, resulting in cathode materials that meet or exceed the performance of virgin materials.
Implementation Method 1
Leaching of the black mass yields a recycling solution of charge material metals and impurities
Implementation Method 2
Subsequent precipitation of charge material precursor results in particles having the formed microstructure from the leach solution
Implementation Method 3
adjusting a concentration of soluble ions in a leach solution based on an intended or targeted microstructure formed in co-precipitated particles from the leach solution
Data Source
AI summary
A recycling process for Lithium-ion (Li-ion) batteries includes a selective leach of charge material metals followed by impurity control for effecting microstructures such as a pore volume and surface area for optimal structures and charge performance. Particle characteristics having a favorable effect on performance correlate with soluble impurities in a recycling leach solution formed from spent charge material in a battery recycling stream. Spent batteries yield a black mass of agitated, comingled cathode material, anode material and current collectors. Leaching of the black mass yields a recycling solution of charge material metals and impurities. Selective adjustment of these impurities through adding and/or separating soluble ions in the solution drives formation of internal voids, surface area and pore volume in the resulting cathode material.