Aqueous Positive Electrode Slurry With Kosmotropic Anion Stabilization
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Solution Overview
Problem
Existing lithium secondary battery electrodes using organic solvents and fluorine-based polymers are environmentally unfriendly and unstable in aqueous systems, leading to reduced performance and lifetime due to side reactions between water and active materials, especially for high-capacity positive electrode active materials like high-nickel lithium metal oxide.
Innovation Solution
An aqueous slurry composition for positive electrodes containing a kosmotropic anion-based metal salt, an aqueous polymer, and a positive electrode active material, which stabilizes the interface and suppresses pH changes, allowing for the use of high-capacity materials like high-nickel lithium metal oxide, and includes a conductive material for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an aqueous process using water and cellulose-based polymers is used to replace organic solvents and fluorine-based polymers, then environmental friendliness is improved, but side reactions between water and electrode active material cause instability and reduce battery performance
Solution Approach 1:
The patent introduces a kosmotropic anion (such as sulfate, phosphate, or carboxylate ions) as an intermediary substance in the aqueous electrolyte. This anion mediates between water and the electrode active material by forming a protective solvation shell around the active material particles, preventing direct contact and reaction with water molecules. This resolves the contradiction by enabling aqueous processing while maintaining material stability through the mediating effect of the kosmotropic anion.
Solution Approach 2:
The patent changes the chemical parameters of the aqueous system by selecting specific kosmotropic anions with high charge density and strong hydration capability. These anions fundamentally alter the water structure and reactivity around the active material, transforming the aqueous environment from one that causes degradation to one that stabilizes the active material. This parameter change enables the use of water-based processes with moisture-sensitive high-capacity materials.
2Quantity of substance
If high-capacity positive electrode active materials such as high-nickel lithium metal oxide are used, then battery capacity is improved, but moisture sensitivity increases causing instability in aqueous systems
Solution Approach 1:
The kosmotropic anion serves as a protective intermediary between the moisture-sensitive high-nickel active material and water molecules. The anion's strong electrostatic field creates a barrier that prevents water from approaching and reacting with the high-capacity active material, thereby enabling the use of these high-performance materials in aqueous processing without compromising their stability.
Solution Approach 2:
The patent changes the electrolyte composition parameters by introducing kosmotropic anions that fundamentally alter the interfacial chemistry between the active material and aqueous environment. This parameter change suppresses the inherent moisture sensitivity of high-nickel materials, allowing them to maintain their high capacity characteristics while achieving stability in the aqueous system.
3Productivity
If water-based processing is used, then productivity is improved, but corrosion of current collector occurs due to increased basicity from side reactions
Solution Approach 1:
The kosmotropic anion acts as a protective intermediary that prevents direct interaction between water and the current collector surface. By forming a stable ionic environment around the active material particles, the anion prevents the generation of hydroxide ions through side reactions, thereby eliminating the root cause of current collector corrosion while maintaining the advantages of water-based processing.
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 aqueous slurry composition ensures chemical stability and excellent charge-discharge performance of positive electrodes, is environmentally friendly, and reduces production costs by eliminating the need for organic solvents and fluorine-based polymers, while enabling the use of high-capacity active materials.
Implementation Method 1
an aqueous electrolyte containing water and a metal salt containing a kosmotropic anion
Data Source
AI summary
An aspect of the present disclosure relates to an aqueous slurry composition for a positive electrode that can replace the existing positive electrode slurry composition using organic solvents and fluorine-based polymers. The aqueous slurry composition for a positive electrode contains an aqueous electrolyte containing a metal salt containing a kosmotropic anion and water, a positive electrode active material, and an aqueous polymer.