Transition Metal Hydroxide Precursor Synthesis via Atmosphere Switching
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Solution Overview
Problem
Current methods for manufacturing transition metal-containing composite hydroxides as precursors for positive electrode active materials in non-aqueous electrolyte secondary batteries are inefficient, requiring time to switch reaction atmospheres, which hampers productivity, and do not adequately improve output characteristics for electric vehicle batteries without compromising battery capacity and cycling characteristics.
Innovation Solution
A method for producing transition metal-containing composite hydroxides with a specific particle structure and composition, involving a nucleation and particle growth process with controlled pH and atmosphere switching, allowing continuous raw material solution supply during atmosphere changes, resulting in secondary particles with a center section and layered structure that enhances electrical connectivity and surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used to manufacture transition metal-containing composite hydroxides, then the manufacturing process can be completed, but the productivity is low due to time-consuming atmosphere switching
Solution Approach 1:
The patent maintains continuous supply of raw material solution throughout the atmosphere switching process, eliminating idle time. The atmosphere is switched from non-oxidizing to oxidizing without stopping the manufacturing process, allowing the reaction to proceed continuously while adapting to different particle growth stages.
Solution Approach 2:
The patent dynamically adjusts the atmosphere conditions during the particle growth process based on the growth stage. The atmosphere switching timing is controlled to coincide with specific particle growth phases, optimizing the particle structure formation while maintaining continuous production.
2Reliability
If particles with small size are used, then the specific surface area increases and electrode resistance decreases, but the particle size distribution may become wide causing selective deterioration
Solution Approach 1:
The patent employs periodic atmosphere switching during the particle growth process. The atmosphere alternates between non-oxidizing and oxidizing conditions at specific intervals, which controls the particle growth rate and results in uniform particle size distribution while maintaining small particle size.
Solution Approach 2:
The patent changes the atmosphere parameter (oxidizing vs. non-oxidizing) at different stages of particle growth. This parameter change controls the growth kinetics, ensuring that particles grow to a uniform small size without developing wide size distribution that would lead to selective deterioration.
3Manufacturing precision
If the reaction atmosphere is switched frequently to control particle structure, then the particle structure can be optimized, but the manufacturing complexity increases
Solution Approach 1:
The patent divides the particle growth process into distinct stages with specific atmosphere conditions. The first particle growth process uses a non-oxidizing atmosphere, followed by atmosphere switching to oxidizing for the second particle growth process. This segmentation allows precise control of particle structure through controlled atmosphere transitions.
4Manufacturing precision
If the particle growth process is extended to improve particle uniformity, then the particle size distribution narrows, but the manufacturing time increases
Solution Approach 1:
The patent uses periodic atmosphere switching to accelerate particle uniformity achievement. By alternating between non-oxidizing and oxidizing atmospheres at optimized intervals, the particle growth is controlled to reach uniform size distribution faster than continuous single-atmosphere processes would allow.
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 simultaneous improvement of battery capacity, output characteristics, and cycling characteristics, while allowing for efficient industrial-scale production of the positive electrode active material, thereby enhancing the performance of non-aqueous electrolyte secondary batteries.
Implementation Method 1
a nucleation process for performing nucleation by controlling the pH value of a nucleation aqueous solution that includes a metal compound that includes has at least a transition metal and an ammonium ion donor
Implementation Method 2
a particle growth process that causes nuclei to grow by controlling the pH value of a particle growth aqueous solution that includes the generated nuclei
Implementation Method 3
a nucleation process for performing nucleation by controlling the pH value of a nucleation aqueous solution that includes a metal compound that includes has at least a transition metal and an ammonium ion donor
Data Source
AI summary
The presently disclosed subject matter is directed to a positive electrode active material for a non-aqueous electrolyte secondary battery including a lithium transition metal-containing composite oxide, comprising secondary particles formed by aggregates of primary particles. The secondary particles comprise: an outer-shell section formed by an aggregate of the primary particles; at least one aggregate section formed by an aggregate of primary particles and existing on an inside of the outer-shell section, and electrically and structurally connected to the outer-shell section; and at least one space section existing on the inside of the outer-shell section and in which there are no primary particles. The average particle size of the secondary particles being within the range 1 μm to 15 μm, an index [(d90-d10)/average particle size] that indicates a spread of a particle size distribution of the secondary particles being 0.7 or less, and the surface area per unit volume being 1.7 m2/cm3 or greater.