Cobalt Hydroxide Carbonate Precursor for Lithium-Ion Battery Cathodes
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Solution Overview
Problem
Current methods for producing cobalt-based cathode materials for lithium-ion batteries face challenges in achieving high energy density, electrochemical stability, and cost-effectiveness due to issues with particle size distribution, sodium impurities, and high processing temperatures, which affect the electrochemical performance and packing density of the materials.
Innovation Solution
A cobalt hydroxide carbonate compound with a malachite-rosasite mineral structure is used as a precursor, doped with elements like Al, Mn, and Mg, produced through a Na2CO3 precipitation process at elevated temperatures with CO2 evacuation, allowing for a spherical morphology and homogeneous dopant distribution, which enhances energy density and reduces sodium impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If high sintering temperature is used to increase particle size and packing density, then volumetric energy density is improved, but process cost and energy consumption increase
Solution Approach 1:
The patent applies preliminary action by pre-forming spherical cobalt precursor particles with controlled size and morphology before the sintering process. This pre-shaping allows the final sintering to occur at lower temperatures since the particle size and packing density are already optimized in the precursor, eliminating the need for high-temperature sintering to achieve the desired particle characteristics.
Solution Approach 2:
The patent changes the parameters of the cobalt precursor (particle size, morphology, density) through controlled precipitation processes before sintering. By adjusting precipitation conditions such as pH, temperature, and additives, the precursor particles are formed with optimal characteristics that translate to high packing density in the final product without requiring high sintering temperatures.
2Manufacturing precision
If high sintering temperature is used to achieve target particle size, then particle size distribution is improved, but electrochemical performance deteriorates due to high Li to Co stoichiometry
Solution Approach 1:
The patent uses preliminary action by forming spherical cobalt precursor particles with precise size control through precipitation processes before sintering. This pre-formed spherical morphology and controlled particle size distribution are maintained through lower-temperature sintering, preventing the formation of excessive Li2CO3 and maintaining optimal Li to Co stoichiometry for electrochemical performance.
Solution Approach 2:
The patent changes the sintering temperature parameter from conventional high temperatures to lower temperatures (900-1000°C), combined with optimized precursor characteristics. This parameter change allows achieving the desired particle size distribution without the harmful side effects of high-temperature sintering on stoichiometry and electrochemical performance.
3Ease of manufacture
If non-shaped cobalt precursor is used to simplify manufacturing, then ease of manufacture is improved, but particle size distribution widens and span increases
Solution Approach 1:
The patent applies preliminary action by implementing a controlled precipitation process that forms spherical cobalt precursor particles with narrow size distribution before sintering. This pre-shaping step is integrated into the manufacturing process, maintaining simplicity while achieving precise particle size control that would be difficult to obtain through post-processing of non-shaped precursors.
Solution Approach 2:
The patent changes the precipitation process parameters (pH, temperature, additives, mixing rate) to control the morphology and size of cobalt precursor particles. By optimizing these parameters, spherical particles with narrow size distribution are formed directly during precipitation, eliminating the need for complex post-processing while maintaining manufacturing simplicity.
4Volume of moving object
If high Li to Co ratio is used during sintering to achieve target particle size, then particle growth is improved, but electrochemical performance deteriorates
Solution Approach 1:
The patent uses preliminary action by pre-forming spherical cobalt precursor particles with controlled size and morphology before sintering. This eliminates the need to use high Li to Co ratios for particle growth, as the particle size is already optimized in the precursor. The sintering process only needs to form the oxide structure, not grow particles, preserving the correct stoichiometry.
5Ease of manufacture
If conventional precipitation process is used to produce cobalt precursor, then manufacturing cost is reduced, but sodium impurity content increases
Solution Approach 1:
The patent changes the precipitation process parameters, specifically using ammonium carbonate or ammonium bicarbonate instead of sodium carbonate, and optimizing pH control during precipitation. This parameter change effectively reduces sodium impurity content in the cobalt precursor while maintaining the cost-effectiveness and simplicity of the precipitation 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
The approach results in a high-quality cathode material with improved electrochemical stability, increased energy density, and reduced processing costs by achieving a narrow particle size distribution and effective dopant distribution, while minimizing sodium impurities.
Implementation Method 1
a cobalt based hydroxide carbonate compound which is prepared by a precipitation process using sodium carbonate
Implementation Method 2
produced through a Na2CO3 precipitation process at elevated temperatures with CO2 evacuation
Data Source
Figure 1~2
Figure 3~4
Figure 5a
AI summary
A method for manufacturing a cobalt based hydroxide carbonate compound having a malachite-rosasite mineral structure, comprising the steps of: - providing an first aqueous solution comprising a source of Co, - providing a second aqueous solution comprising Na2CO3, - mixing both solutions in a precipitation reactor at a temperature above 70°C, thereby precipitating a cobalt based hydroxide carbonate compound whilst evacuating from the reactor any CO2 formed by the precipitation reaction, wherein the residence time of the compound in the reactor is between 1 and 4 hours, and - recovering the cobalt based hydroxide carbonate compound. The cobalt based hydroxide carbonate compound is used as a precursor of a lithium cobalt based oxide usable as an active positive electrode material in lithium ion batteries.