Positive Electrode Material Processing to Limit Agglomeration
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Solution Overview
Problem
Existing methods for preparing positive electrode active materials face challenges in achieving high energy density, large size, high capacity, and improved productivity while minimizing particle agglomeration and electrical resistance, often requiring complex processes and costly grain growth accelerators.
Innovation Solution
A method involving a co-precipitation reaction at specific pH ranges, followed by heat treatments with aluminum and zirconium dopants, allows for the synthesis of nickel-based composite hydroxide particles, which are then processed into hollow secondary particles and further treated to form single particles without alkaline accelerators, reducing agglomeration and electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If alkaline grain growth accelerators are used to prepare positive electrode active materials at high firing temperatures, then particle growth and densification are improved, but particle agglomeration increases and electrical resistance increases
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating aluminum and zirconium dopants in specific ratios (Al:Zr = 5:1 to 20:1) to achieve grain growth and densification without using alkaline accelerators, thereby avoiding particle agglomeration and resistance increase
Solution Approach 2:
The patent replaces expensive and harmful alkaline grain growth accelerators with aluminum and zirconium dopants that serve as both dopants and grain growth promoters, eliminating the need for separate accelerator additives and their subsequent removal processes
2Quantity of substance
If complex preparation processes are used to achieve high energy density and large particle size, then battery capacity is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent combines multiple functions into a single dopant system: aluminum and zirconium serve simultaneously as dopants for structural stability, grain growth promoters for particle size control, and sintering aids for densification, eliminating the need for separate additives and processes
Solution Approach 2:
The aluminum-zirconium dopant system performs multiple functions throughout the preparation process: controlling precipitation morphology, promoting grain growth during firing, enhancing densification, and stabilizing the crystal structure, making the process simpler and more economical
3Stability of the object's composition
If high firing temperatures are used to produce single particles, then particle density and structural stability are improved, but particle agglomeration increases and electrical resistance increases
Solution Approach 1:
The patent changes the chemical composition by incorporating aluminum and zirconium dopants that enable structural stability and grain growth at lower firing temperatures, preventing particle agglomeration while maintaining density and stability
Solution Approach 2:
The aluminum-zirconium dopant system acts as an intermediary that facilitates grain growth and densification at lower temperatures by forming stable intermediate phases that promote sintering without causing particle agglomeration
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 enables the production of structurally stable, high-capacity positive electrode active materials with improved cycle-life and economic efficiency, simplifying the process and enhancing productivity.
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
Implementation Method 3
pulverizing the secondary particles
Implementation Method 4
performing a second heat treatment to obtain a positive electrode active material
Data Source
AI summary
A method of preparing a positive electrode active material is disclosed. The method may include 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, mixing the nickel-based composite hydroxide, an anhydrous lithium hydroxide, an aluminum 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 (e.g., water-soluble) solvent, and then performing a second heat treatment to obtain a positive electrode active material.