Delithiated Battery Material Washing for Low-Ion Impurity Removal
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Solution Overview
Problem
Existing processes for delithiating lithium nickel oxide materials to produce battery materials suffer from high levels of mono or multi-valent ion impurities, which affect the quality and performance of electrochemical cells.
Innovation Solution
A process involving the use of aqueous media to wash delithiated electrochemically active compositions, specifically through reslurry and displacement cake washes, to reduce the conductivity of the aqueous medium below 1,000 micro-Siemens per centimeter, effectively removing impurities such as calcium, magnesium, sodium, chloride, and chlorate ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional delithiation processes are used, then lithium can be removed from the electrochemically active composition, but high levels of mono or multi-valent ion impurities remain in the delithiated material
Solution Approach 1:
The washing process is divided into multiple sequential stages using different aqueous mediums: first a neutral pH aqueous medium to remove soluble impurities, then an acidic aqueous medium to remove basic impurities, and finally a neutralizing aqueous medium to adjust the final pH. This segmented approach targets different types of impurities with specialized washing solutions, achieving thorough purification without compromising lithium removal efficiency.
Solution Approach 2:
The invention controls and adjusts the pH parameter of each washing stage to optimize impurity removal. The first wash uses neutral pH (6-8), the second uses acidic pH (2-4), and the third uses neutralizing pH (7-9). By varying the pH parameter across stages, the process effectively removes different classes of impurities (basic, acidic, and amphoteric) while maintaining efficient lithium extraction.
2Manufacturing precision
If multiple washing steps are performed to remove impurities, then purity increases, but process complexity and time increase
Solution Approach 1:
Each aqueous medium is designed to perform multiple functions: the neutral pH medium removes soluble salts and prepares the surface, the acidic medium removes basic impurities and activates the material, and the neutralizing medium adjusts pH and removes acidic impurities. This multi-functionality reduces the need for additional specialized treatment steps, simplifying the overall process while maintaining high purification effectiveness.
Solution Approach 2:
The process systematically discards each washing medium after it has fulfilled its purification function, moving to the next medium in sequence. Each spent medium is discarded after removing its target impurities, and the solid delithiated material is recovered and advanced to the next washing stage. This systematic discard-and-recover approach manages process complexity by clearly defining when each medium's function is complete.
3Manufacturing precision
If extensive washing is performed to achieve low conductivity, then impurity removal improves, but processing time increases
Solution Approach 1:
The first neutral pH wash is performed as a preliminary action to remove the bulk of soluble impurities and prepare the material surface before the more specialized acidic and neutralizing washes. This preliminary removal of easily soluble impurities reduces the burden on subsequent washing stages, allowing them to focus on more tenaciously bound impurities and achieve target conductivity levels more efficiently.
Solution Approach 2:
The invention replaces extended mechanical washing time with chemical optimization of the aqueous mediums. By carefully selecting the pH and composition of each washing medium, the process achieves efficient impurity removal through chemical affinity and solubility differences rather than relying solely on prolonged mechanical agitation and rinsing, thereby reducing total processing time while maintaining low final conductivity.
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 process significantly reduces impurity levels, resulting in a stable battery material with improved conductivity and performance characteristics, suitable for use in electrochemical cells.
Implementation Method 1
contacting the second intermediate product with a stream of a second aqueous medium until a conductivity of the stream of the second aqueous medium after contacting the second intermediate product is below about 1,000 micro-Siemens per centimeter
Implementation Method 2
the impurities include mono or multi-valent ions including calcium, magnesium, sodium, chloride, chlorite, and/or chlorate
Data Source
AI summary
Disclosed is a process for removing impurities from an intermediate product in battery material production including a) contacting a first intermediate product with a first aqueous medium to obtain a second intermediate product; and b) contacting the second intermediate product with a stream of a second aqueous medium until a conductivity of the stream of the second aqueous medium after contacting the second intermediate product is below about 1,000 micro-Siemens per centimeter (μS/cm).