Co-precipitation Precursor for Li-Ion Cathode Particle Control
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Solution Overview
Problem
Current methods for producing lithium cobalt oxide cathodes for lithium-ion batteries face challenges in achieving uniform particle distribution and batch-to-batch reproducibility due to high-temperature processing, which affects energy density and chemical stoichiometry.
Innovation Solution
A method involving the formation of a precursor co-precipitate material using an aqueous solution of manganese and cobalt sulfates, with pH control and agitation to produce spherical particles of specific size and composition, represented by MnxMyCoz(OH)2, which are then filtered, washed, and dried to create a high-density cathode active material for lithium-ion batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If high-temperature calcining is used to produce large LiCoO2 particles, then particle size increases, but uniform particle distribution and batch-to-batch reproducibility deteriorate
Solution Approach 1:
The patent applies preliminary action by forming a precursor co-precipitate material with controlled particle size and uniform distribution before the final calcination step. The precursor particles are prepared in advance with specific size characteristics (D50 > 15 microns) and uniform distribution, which are then maintained during subsequent processing to achieve both large final particle size and uniform distribution.
Solution Approach 2:
The patent employs parameter changes by controlling the pH range (10-12) during co-precipitation and maintaining constant temperature (30-65°C) to optimize particle formation. These parameter controls during precursor formation enable the production of particles with desired size and uniformity that are preserved through subsequent high-temperature calcination.
2Volume of moving object
If high-temperature calcining is used to produce large LiCoO2 particles, then particle size increases, but chemical stoichiometry control deteriorates
Solution Approach 1:
The patent applies preliminary action by establishing the correct chemical stoichiometry in the precursor co-precipitate material before high-temperature calcination. The precursor is formed with controlled composition and uniform particle distribution, ensuring that the desired stoichiometry is locked in before the final heating step that produces the cathode material.
Solution Approach 2:
The patent employs parameter changes by maintaining constant pH (10-12) and temperature (30-65°C) during co-precipitation to ensure precise control of metal ion ratios and chemical composition. These controlled parameters during precursor formation guarantee accurate stoichiometry that is preserved through subsequent processing.
3Ease of manufacture
If conventional methods are used to produce cathode material, then manufacturing process is simple, but energy density and battery performance deteriorate
Solution Approach 1:
The patent applies preliminary action by introducing a co-precipitation step that forms precursor particles with optimized characteristics (large size, uniform distribution, controlled composition) before final calcination. This preliminary particle formation step enables the final cathode material to achieve high energy density while maintaining a relatively straightforward overall manufacturing process.
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 results in cathode active materials with large particle sizes and uniform distribution, enhancing the energy density and reversible lithium-ion extraction capacity of lithium-ion batteries, thereby improving battery performance and reproducibility.
Implementation Method 1
a NH4OH solution is added to the aqueous solution to form a particulate solution containing irregular secondary particles of the precursor co-precipitate material
Implementation Method 2
A constant pH in the range of 10-12 is also maintained in the particulate solution by adding a basic solution to the particulate solution
Implementation Method 3
the particulate solution is also agitated to form spherical co-precipitate particles from the irregular secondary particles
Implementation Method 4
the spherical co-precipitate particles are filtered from the particulate solution
Implementation Method 5
the spherical co-precipitate particles are filtered from the particulate solution, washed, and dried
Data Source
AI summary
The disclosed embodiments relate to the manufacture of a precursor co-precipitate material for a cathode active material composition. During manufacture of the precursor co-precipitate material, an aqueous solution containing at least one of a manganese sulfate and a cobalt sulfate is formed. Next, a NH4OH solution is added to the aqueous solution to form a particulate solution comprising irregular secondary particles of the precursor co-precipitate material. A constant pH in the range of 10-12 is also maintained in the particulate solution by adding a basic solution to the particulate solution.