Coated Lithium-Nickel Composite Oxide Particles for Battery Stability
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Solution Overview
Problem
Nickel-based lithium-nickel composite oxide particles are prone to high reactivity with water and carbon dioxide, leading to the formation of impurities like lithium hydroxide and lithium carbonate, which affect battery stability and production processes, requiring costly controlled environments for handling and storage.
Innovation Solution
Coating nickel-based lithium-nickel composite oxide particles with a carboxyl group-containing molecule or organic sulfur compound to form a self-assemble monolayer that suppresses moisture and carbon dioxide absorption, enhancing environmental stability and adhesion of the coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-based lithium-nickel composite oxide particles with high nickel content are used to achieve high capacity, then the theoretical capacity is improved, but the reactivity with water and carbon dioxide increases, leading to impurity formation and safety issues
Solution Approach 1:
A thin film coating layer is formed on the surface of the nickel-based lithium-nickel composite oxide particles using a fluorine-containing polymer. This coating layer acts as a protective barrier that suppresses the reactivity between the high-nickel content particles and water or carbon dioxide, preventing impurity formation while maintaining the high capacity benefits
Solution Approach 2:
The invention creates a composite structure by combining nickel-based lithium-nickel composite oxide particles with a fluorine-containing polymer coating. This composite material approach allows the inner high-nickel particles to provide high capacity while the outer fluorine-containing polymer layer provides chemical stability and safety
2Quantity of substance
If nickel-based lithium-nickel composite oxide particles are used to achieve high capacity, then the theoretical capacity is improved, but the particles absorb moisture and carbon dioxide easily, causing slurry viscosity increase and gelation
Solution Approach 1:
The fluorine-containing polymer coating forms a thin film barrier on the particle surface that prevents moisture and carbon dioxide from reaching and reacting with the nickel-based particles. This eliminates the slurry viscosity increase and gelation problems that would otherwise occur during production
Solution Approach 2:
The fluorine-containing polymer acts as an intermediary layer between the nickel-based particles and the environment (moisture, carbon dioxide). This intermediate coating prevents direct contact and harmful reactions while allowing the particles to be handled in normal production conditions
3Reliability
If a fluorine-containing polymer coating is applied to suppress moisture absorption, then the environmental stability is improved, but the coating layer may detach during slurry production
Solution Approach 1:
The invention optimizes several parameters to ensure coating stability: the fluorine-containing polymer's glass transition temperature is set between -50°C and 0°C, the coating amount is controlled at 0.1-10 nmol/m², and the particle surface area is maintained at 0.03-0.15 m²/g. These parameter changes ensure the coating remains adherent during slurry production while providing environmental stability
4Reliability
If controlled environment facilities are introduced to prevent impurity formation, then the production process reliability is improved, but the facility introduction cost and running costs increase
Solution Approach 1:
The fluorine-containing polymer coating serves as an intermediary protective layer that allows the nickel-based particles to be handled in normal atmospheric conditions without requiring expensive controlled environment facilities. The coating prevents impurity formation while enabling simple, cost-effective production processes
Solution Approach 2:
Instead of investing in expensive, complex controlled environment facilities, the invention uses a thin, inexpensive fluorine-containing polymer coating that provides the necessary protection. This approach replaces capital-intensive infrastructure with a low-cost material solution
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 coated particles exhibit improved stability and adhesion, allowing for handling in standard atmospheres and reducing the formation of impurities, thus enhancing battery performance and simplifying production processes without the need for expensive controlled environments.
Implementation Method 1
coating surfaces of nickel-based lithium-nickel composite oxide particles with a coating material to form a self-assemble monolayer
Implementation Method 2
a self-assemble monolayer that suppresses moisture and carbon dioxide absorption
Data Source
Figure 1
AI summary
To provide excellent lithium-nickel composite oxide particles which have high environmental stability and are thus capable of suppressing generation of impurities due to absorption of moisture and a carbon dioxide gas, while being prevented from easy separation of a coating film because of high adhesion thereof and having lithium ion conductivity. Coated lithium-nickel composite oxide particles, which are obtained by coating the surfaces of lithium-nickel composite oxide particles with a predetermined coating material, have electrical conductivity and ion conductivity and are capable of suppressing permeation of moisture and a carbon dioxide gas. Consequently, the present invention is able to provide coated lithium-nickel composite oxide particles for positive electrode active materials of lithium ion batteries, which is excellent for use in lithium ion batteries.