Core-Shell Functional Layer Composition for Wet Adhesion and Electrolyte Flow
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Solution Overview
Problem
Conventional electrochemical devices face challenges in achieving excellent wet adhesiveness and electrolyte solution injectability, particularly under high pressing pressure conditions, and require improvements in rate characteristics.
Innovation Solution
A composition for an electrochemical device functional layer comprising a particulate polymer with a core-shell structure, where the core portion has a degree of swelling in electrolyte solution between 1 and 8, and the shell portion has a degree of swelling of 4 or more, with a specific ratio of core to shell swelling, and a volume-average particle diameter between 1.0 μm and 10.0 μm, enhancing wet adhesiveness and electrolyte solution injectability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a functional layer is formed using conventional compositions, then the basic structure is achieved, but wet adhesiveness is insufficient
Solution Approach 1:
The patent applies parameter changes by carefully controlling the glass transition temperatures of polymer A (0°C to 100°C) and polymer B (-50°C to 0°C), along with their specific swelling ratios and particle diameter (1-10 μm). These parameter optimizations enable the functional layer to achieve excellent wet adhesiveness while maintaining ease of manufacture, resolving the contradiction between reliability and ease of manufacture.
Solution Approach 2:
The patent uses composite materials by creating a core-shell structured particulate polymer where polymer A forms the core and polymer B forms the shell. This composite structure combines the advantages of both polymers: polymer A provides structural stability while polymer B enhances wet adhesiveness through its lower glass transition temperature and higher swelling ratio. This composite approach resolves the contradiction by achieving both reliable wet adhesiveness and manufacturability.
2Reliability
If the functional layer structure is optimized for wet adhesiveness, then wet adhesiveness improves, but electrolyte solution injectability deteriorates
Solution Approach 1:
The patent applies local quality by creating distinct regions within the particulate polymer: the core (polymer A) provides structural integrity to maintain porosity for electrolyte injection, while the shell (polymer B) provides localized wet adhesiveness enhancement. This local differentiation resolves the contradiction between wet adhesiveness and electrolyte solution injectability.
Solution Approach 2:
The patent utilizes porous materials by maintaining a porous structure within the functional layer that allows electrolyte solution to penetrate effectively. The specific particle diameter range (1-10 μm) and the core-shell structure create appropriate porosity that facilitates electrolyte injection while simultaneously providing the necessary wet adhesiveness through the polymer composition.
3Reliability
If the functional layer is designed for high wet adhesiveness, then wet adhesiveness improves, but rate characteristics worsen
Solution Approach 1:
The patent applies dynamics by selecting polymers with specific glass transition temperatures that allow the functional layer to exhibit dynamic response to environmental conditions. Polymer B with its lower glass transition temperature (-50°C to 0°C) provides dynamic flexibility that enhances wet adhesiveness while maintaining ion transport pathways for good rate characteristics. This dynamic property resolves the contradiction between wet adhesiveness and rate characteristics.
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 described composition forms a functional layer with improved wet adhesiveness and electrolyte solution injectability, leading to enhanced rate characteristics and cycle performance of electrochemical devices.
Implementation Method 1
the polymer A has a degree of swelling in electrolyte solution SA of not less than a factor of 1 and not more than a factor of 8, the polymer B has a degree of swelling in electrolyte solution SB of a factor of 4 or more
Data Source
AI summary
A composition for an electrochemical device functional layer contains a particulate polymer, a binder, and heat-resistant fine particles. The particulate polymer has a core-shell structure including a core portion formed of a polymer A and a shell portion formed of a polymer B. The polymer A has a degree of swelling in electrolyte solution SA of not less than a factor of 1 and not more than a factor of 8, the polymer B has a degree of swelling in electrolyte solution SB of a factor of 4 or more, and these satisfy a relationship of SB/SA≥1.2. The particulate polymer has a volume-average particle diameter of not less than 1.0 μm and not more than 10.0 μm.