Nickel Cobalt Manganese Hydroxide Precursor Synthesis
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Solution Overview
Problem
Lithium nickel cobalt manganese composite oxide batteries face issues with impurities from the production of nickel cobalt manganese composite hydroxide, leading to decreased crystallinity and capacity due to sulfate radicals and other impurities, which inhibit lithium reaction and require excess negative electrode material, resulting in reduced battery capacity and safety concerns.
Innovation Solution
A process to produce nickel cobalt manganese composite hydroxide with reduced impurities by using an alkali solution of mixed alkali metal hydroxide and carbonate in a crystallization reaction, achieving spherical secondary particles with controlled particle size distribution and low sulfate and chlorine content, enhancing reactivity and crystallinity when mixed with lithium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional coprecipitation process is used to produce nickel cobalt manganese composite hydroxide, then production cost is reduced, but sulfate radicals and other impurities are generated which decrease crystallinity and capacity of the final oxide product
Solution Approach 1:
The patent applies preliminary action by performing a washing step before the crystallization reaction to remove sulfate radicals and other impurities from the nickel cobalt manganese composite hydroxide precursor. This preliminary purification ensures that the subsequent crystallization reaction produces high-crystallinity oxide product without being contaminated by impurities that would otherwise inhibit lithium reaction and reduce capacity.
2Device complexity
If impurity content is not controlled in nickel cobalt manganese composite hydroxide, then production process is simplified, but excess negative electrode material is required which reduces battery capacity
Solution Approach 1:
The washing step performed before crystallization serves as a preliminary action to remove impurities that would otherwise require excess negative electrode material to compensate for. By removing sulfate radicals and other contaminants in advance, the process ensures efficient lithium reaction and maximizes battery capacity without requiring additional negative electrode material.
3Productivity
If conventional production method is used, then production speed is maintained, but particle size distribution is wide and spherical shape is not achieved
Solution Approach 1:
The patent applies parameter changes by controlling the pH value during the crystallization reaction and adjusting reaction temperature and time parameters. These parameter optimizations enable the formation of spherical particles with narrow size distribution while maintaining high production speed. The controlled crystallization process transforms the precipitation kinetics to favor spherical morphology and uniform growth.
4Quantity of substance
If high nickel content is used to increase capacity, then battery capacity increases, but heat stability deteriorates
Solution Approach 1:
The patent applies composite materials by formulating a nickel cobalt manganese composite oxide where nickel provides high capacity, cobalt enhances stability, and manganese contributes to heat stability and structural integrity. This composite approach allows the battery to achieve high capacity from nickel while the cobalt and manganese components maintain heat stability and prevent degradation, resolving the trade-off between capacity and thermal safety.
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 resulting nickel cobalt manganese composite hydroxide with low impurity content and high reactivity produces lithium nickel cobalt manganese composite oxide with improved crystallinity and capacity, addressing the capacity and safety issues of previous battery materials.
Implementation Method 1
a crystallization step in which crystallization is performed in a reaction solution obtained by adding an alkali solution to an aqueous solution
Implementation Method 2
a nickel cobalt manganese composite hydroxide production process by a crystallization reaction
Data Source
AI summary
Providing a nickel cobalt manganese composite hydroxide with low impurity content and high reactivity when synthesizing a positive electrode active material, and which can be used as a precursor of the positive electrode active material for non-aqueous electrolyte secondary batteries with low irreversible capacity. The nickel cobalt manganese composite hydroxide represented by a general formula: NixCoyMnzMt(OH)2+a (wherein x+y+z+t=1, 0.20≤x≤0.80, 0.10≤y≤0.50, 0.10≤z≤ 0.90, 0≤t≤0.10, 0≤a≤0.5, and M is at least one additive element selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, W), the nickel cobalt manganese composite hydroxide comprising: spherical secondary particles formed by aggregation of a plurality of plate-shaped primary particles, wherein the secondary particles have an average particle diameter of 3 µm to 20 µm, a sulfate radical content of 1.0 mass% or less, a chlorine content of 0.5 mass% or less, and a carbonate radical content of 1.0 mass% to 2.5 mass%.