Recycled NMC Cathode Microstructure Control Through Leach Impurity Tuning
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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 involving selective leaching and impurity control in the recycling process, where the concentration of soluble ions in the leach solution is adjusted to form desired microstructures in the cathode material precursor, followed by co-precipitation to achieve targeted microfeatures in the recycled cathode material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional leaching and precipitation methods are used to recycle NMC charge material, then the recycling process is simple and cost-effective, but the resulting cathode material has undetermined and unfavorable microstructures such as internal voids and porosity
Solution Approach 1:
The patent applies parameter changes by systematically adjusting the concentration of soluble ion impurities (such as sodium and lithium ions) in the leach solution to control the microstructure formation during co-precipitation. By varying impurity concentrations within specific ranges, the process achieves desired pore volume, surface area, and internal void characteristics in the cathode material precursor, resolving the contradiction between microstructure precision and process simplicity
Solution Approach 2:
The patent uses soluble ion impurities as intermediaries to mediate the co-precipitation process. These impurities act as structure-directing agents that influence the nucleation and growth of cathode material particles, enabling controlled microstructure formation without requiring complex additional processing steps. The impurities facilitate the formation of desirable pore structures and surface characteristics during the normal recycling workflow
2Productivity
If substantial quantities of recycled cathode materials are incorporated into the recycled product, then recycling efficiency and resource utilization are improved, but it becomes problematic to satisfy customer specifications for performance and physical cathode material characteristics
Solution Approach 1:
The patent enables high-volume recycling while meeting performance specifications by changing the chemical parameters of the leach solution, specifically the concentration of soluble ion impurities. This allows consistent production of cathode material with controlled microstructures that meet customer requirements, even when processing substantial quantities of recycled material. The parameter control ensures reproducible quality across large production batches
Solution Approach 2:
The patent applies preliminary action by adjusting the impurity concentration in the leach solution before the co-precipitation step. This pre-control of chemical conditions ensures that the microstructure formation during precipitation yields the desired pore volume and surface area characteristics, preventing quality issues before they occur and enabling consistent compliance with specifications in high-volume recycling operations
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 formation of cathode materials with controlled microstructures, improving performance and meeting customer specifications, as demonstrated by enhanced cycling performance and microstructure characteristics.
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
Data Source
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Figure 3A~3C
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.