Sulfonate-Coated Lithium Nickel Oxide Cathode for Gas Suppression
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Solution Overview
Problem
Conventional lithium-containing composite oxides used in positive electrodes of non-aqueous electrolyte secondary batteries generate gas during high-temperature storage, compromising battery reliability and charge capacity.
Innovation Solution
A positive electrode active material comprising first lithium nickel oxide particles with an average diameter of 8-30 µm and second lithium nickel oxide particles with an average diameter of ≤6 µm, coated with a sulfonate compound, is used to enhance high-temperature storage characteristics while maintaining charge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a positive electrode active material with small average particle diameter is used to increase charge capacity, then the charge capacity improves, but gas is generated during high-temperature storage, worsening battery reliability
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the interior particles maintain small size for high capacity while the exterior surface is coated with a protective layer. Specifically, small particles (≤6 μm) provide high charge capacity, while a coating layer containing sulfonate compounds is formed on the particle surfaces to suppress gas generation during high-temperature storage, thus resolving the contradiction between capacity and reliability
Solution Approach 2:
The patent uses composite materials by combining small lithium-containing composite oxide particles with a protective coating layer containing sulfonate compounds. This composite structure allows the inner small particles to contribute to high charge capacity while the outer coating layer suppresses gas generation during high-temperature storage, simultaneously achieving both high capacity and high reliability
2Reliability
If a coating layer is formed on the surface of the positive electrode active material to suppress gas generation, then high-temperature storage characteristics improve, but the charge capacity decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the coating layer composition to contain sulfonate compounds at specific concentrations (0.1-5 mass% relative to the positive electrode active material). This controlled parameter adjustment allows the coating to effectively suppress gas generation during high-temperature storage while minimizing its negative impact on charge capacity, thus resolving the contradiction between storage characteristics and capacity
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 proposed material improves high-temperature storage characteristics and suppresses the decrease in charge capacity by controlling gas generation, thereby enhancing battery reliability.
Implementation Method 1
a sulfonate compound represented by general formula (I) is present on surfaces of second lithium nickel oxide particles
Data Source
Figure 1
AI summary
A positive electrode active material for nonaqueous electrolyte secondary batteries comprises first lithium nickel oxide particles that have an average particle diameter of 8 µm to 30 µm inclusive, and second lithium nickel oxide particles that have an average particle diameter of 6 µm or less. A sulfonic acid compound represented by general formula I is present on the surfaces of the second lithium nickel oxide particles. If X mass% is the ratio of the mass of a sulfonic acid compound that is present on the surfaces of the first lithium nickel oxide particles to the mass of the first lithium nickel oxide particles and Y mass% is the ratio of the mass of the sulfonic acid compound that is present on the surfaces of the second lithium nickel oxide particles to the mass of the second lithium nickel oxide particles, X and Y satisfy the relational expression Y > X. In the formula, A represents a group 1 element or a group 2 element; R represents a hydrocarbon group; and n is 1 or 2.