Aluminum-Doped Cobalt Oxide Coprecipitation for Uniform High Tap Density
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Solution Overview
Problem
Existing methods for preparing aluminum doped cobalt oxide result in poor cycle performance, charge-discharge performance, and low tap density due to uneven aluminum doping and low particle size uniformity.
Innovation Solution
A method involving coprecipitation reactions where a cobalt salt solution is added first, followed by an aluminum cobalt solution after reaching a specific particle size, with subsequent aging, dehydration, washing, and calcination to produce high-density aluminum doped cobalt oxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If aluminum doping is performed using conventional methods, then aluminum doping is achieved, but the doping is uneven and particle size uniformity is poor
Solution Approach 1:
The patent performs preliminary coprecipitation of cobalt salt solution and alkaline solution to form cobalt hydroxide particles with controlled size (D50=2.0-2.5 μm) before adding aluminum-containing solution. This preliminary action ensures that aluminum doping occurs on uniformly sized particles, improving doping uniformity and particle size distribution, which directly addresses the contradiction between manufacturing precision and reliability
Solution Approach 2:
The patent segments the doping process into two distinct stages: first forming cobalt hydroxide particles through coprecipitation, then adding aluminum-containing solution for doping. This segmentation allows independent control of particle formation and doping processes, ensuring uniform aluminum distribution without compromising cycle performance
2Quantity of substance
If conventional preparation methods are used, then aluminum doped cobalt oxide is produced, but the tap density is low
Solution Approach 1:
The patent changes key process parameters including feed rates (cobalt salt solution: 220-260 L/h, alkaline solution: 50-150 L/h), pH value (9-11), and particle size control (D50=2.0-2.5 μm to 3.5-4.0 μm) to optimize particle morphology and density. These parameter changes result in high tap density (2.36 g/cm³) and high energy density lithium cobalt oxide products
Solution Approach 2:
The patent replaces conventional mechanical mixing and drying methods with coprecipitation reaction followed by controlled aging and dehydration. This substitution enables better control of particle formation and densification, achieving high tap density without compromising productivity
3Quantity of substance
If high voltage lithium cobalt oxide is developed to increase energy density, then gram volume increases, but manufacturing complexity increases
Solution Approach 1:
The patent merges the doping process with the particle formation process by performing coprecipitation of cobalt and aluminum ions simultaneously. This merging eliminates separate doping steps, reducing process complexity while achieving uniform high-level aluminum doping (0.5-1.0 mol%) and high energy density products
Solution Approach 2:
The coprecipitation process serves multiple functions simultaneously: it forms particles, controls size distribution, and performs aluminum doping in one integrated operation. This multi-functionality reduces the number of process steps and equipment requirements, lowering manufacturing complexity while maintaining high energy density
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 method ensures uniform aluminum doping, enhancing the tap density and cycle performance of batteries, improving charge-discharge capabilities and current density.
Implementation Method 1
adding a cobalt salt solution, an alkaline solution and an oxidizer to a reactor for coprecipitation reaction
Implementation Method 2
aging, dehydrating, washing and drying the aluminiferous cobalt oxyhydroxide slurry obtained in step 1
Implementation Method 3
aging, dehydrating, washing and drying the aluminiferous cobalt oxyhydroxide slurry obtained in step 1
Implementation Method 4
calcining the aluminiferous cobalt oxyhydroxide powder obtained in step 2, thus obtaining high density aluminum doped cobalt oxide
Data Source
AI summary
The present invention discloses a preparation method for high density aluminum doped cobalt oxide, which comprises following steps: 1) adding a cobalt salt solution, an alkaline solution and an oxidizer to a reactor for reaction; adding an aluminum cobalt solution to the reaction system for reaction; stopping adding the aluminum cobalt solution after D50 reaches 3.5-4.0 μm, stopping the reaction when D50 reaches the desired particle size, thus obtaining aluminiferous cobalt oxyhydroxide slurry; 2) aging, dehydrating, washing and drying the aluminiferous cobalt oxyhydroxide slurry, thus obtaining aluminiferous cobalt oxyhydroxide powder; 3) calcining the aluminiferous cobalt oxyhydroxide powder, thus obtaining the target object. With the method of the present invention, doped aluminum can be perfectly embedded into cobalt oxide lattices, thus effectively enhancing the tap density and uniformity of aluminum doped cobalt oxide and improving the cycle performance and charge-discharge performance of batteries.