Positive Electrode Material Processing for Low-Agglomeration Single Particles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for preparing positive electrode active materials for high-energy density lithium batteries face challenges such as particle agglomeration, increased electrical resistance due to residual grain growth accelerators, and decreased cycle-life, particularly when synthesizing single particles at high temperatures or with complex processes.
Innovation Solution
A method involving a co-precipitation reaction at specific pH ranges followed by heat treatments with aluminum and zirconium dopants to produce nickel-based composite hydroxide, forming hollow secondary particles that are easily pulverized into single particles, eliminating the need for alkaline grain growth accelerators and reducing agglomeration, while maintaining structural stability and cycle-life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If high temperature firing is used to prepare single particles, then particle morphology is improved, but particle agglomeration increases and electrical resistance increases due to residual grain growth accelerators
Solution Approach 1:
The patent performs preliminary doping of aluminum and zirconium into the particle structure before the main firing process. This preliminary action modifies the particle properties in advance, enabling single particle formation at lower temperatures without requiring alkaline grain growth accelerators, thereby preventing both agglomeration and residual impurity formation
Solution Approach 2:
The patent changes the chemical composition parameters by introducing aluminum and zirconium dopants in specific ratios. This parameter modification alters the thermal and structural properties of the particles, allowing them to maintain structural integrity and disperse as single particles at lower firing temperatures without agglomeration
2Shape
If alkaline grain growth accelerators are used to prepare single particles, then particle formation is improved, but residual impurities increase causing increased electrical resistance
Solution Approach 1:
The patent introduces aluminum and zirconium as intermediary dopant elements that facilitate single particle formation without acting as grain growth accelerators. These intermediaries modify the particle formation mechanism, enabling single particle structure to develop through doping effects rather than accelerator-driven grain growth, thus avoiding residual impurity formation
Solution Approach 2:
The patent replaces expensive and problematic alkaline grain growth accelerators with aluminum and zirconium dopants that become integral parts of the particle structure. These dopants serve their function during particle formation and then remain as stable, non-interfering components, effectively replacing the disposable accelerators that leave harmful residues
3Manufacturing precision
If complex washing processes are used to remove residual impurities, then purity is improved, but process complexity and cost increase
Solution Approach 1:
The patent converts the potential harm of doping elements into a benefit by using aluminum and zirconium doping to prevent the formation of harmful residues in the first place. The doping process itself becomes the purification mechanism, eliminating the need for complex washing processes to remove accelerator residues, as no such residues are generated
4Use of energy by moving object
If high nickel content is used to achieve high energy density, then energy density is improved, but structural stability decreases
Solution Approach 1:
The patent applies local quality modification by introducing aluminum and zirconium dopants at specific locations within the particle structure. These dopants are incorporated into the crystal lattice at strategic positions, locally reinforcing the structure where needed while maintaining the high nickel content for energy density, thus achieving both high energy density and structural stability
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 method enables the production of structurally stable, high-energy density positive electrode active materials with reduced electrical resistance and improved cycle-life, enhancing productivity and economic efficiency without complex washing processes.
Implementation Method 1
performing a co-precipitation reaction including a first step of reacting at a pH range of about pH 11 to about pH 12 and a second step of reacting at a pH lower than the first step for a mixture of a nickel precursor and a metal precursor to obtain a nickel-based composite hydroxide
Implementation Method 2
subjecting to a first heat treatment to produce hollow secondary particles including layered lithium nickel-based composite oxide
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of preparing a positive electrode active material includes: performing a coprecipitation reaction including a first step of reacting at a pH range of about pH 11 to about pH 12 and a second step of reacting at a pH lower than the first step for a mixture of a nickel precursor and a metal precursor to obtain a nickel-based composite hydroxide, mixing the nickel-based composite hydroxide, an anhydrous lithium hydroxide, an aluminium raw material, and a zirconium raw material and subjecting to a first heat treatment to produce hollow secondary particles, pulverizing the secondary particles, and adding and mixing the pulverized resultant, a cobalt coating raw material, and a zirconium coating raw material into an aqueous solvent, and then performing a second heat treatment to obtain a positive electrode active material.