Electrode Binder Composition for Fibrous Conductive Material Dispersion

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Solution Overview

Problem

Conventional methods fail to achieve good dispersion of fibrous conductive materials in electrochemical devices, leading to poor cycle characteristics.

Innovation Solution

A binder composition containing a first polymer with nitrile group-containing monomer units and aliphatic conjugated diene or alkylene structural units, and a second polymer with a specific polyoxyethylene group-containing structural unit, improves dispersibility and cycle characteristics of electrochemical devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fibrous conductive material is used to impart electrical conductivity to the electrode mixed material layer, then electrical conductivity is improved, but the fibrous conductive material has a high tendency to aggregate, resulting in poor dispersibility

Engineering Contradiction:

Improveelectrical conductivityVSAvoiddispersibility

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses a binder composition as an intermediary substance between the fibrous conductive material and the electrode active material. The binder composition, containing specific polymers with nitrile groups and polyoxyethylene groups, mediates the interaction between conductive materials and active materials, enabling good dispersion while maintaining electrical conductivity. This resolves the contradiction by providing a medium that prevents aggregation without compromising conductivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite binder composition combining multiple polymer components with specific functional groups. The composite structure includes polymers with nitrile groups (for conductivity and adhesion) and polyoxyethylene groups (for dispersion and compatibility), which work synergistically to achieve both good dispersibility of fibrous conductive materials and maintained electrical conductivity in the electrode mixed material layer.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional binder compositions are used with fibrous conductive materials, then the electrode mixed material layer can be formed, but the electrochemical device displays poor cycle characteristics

Engineering Contradiction:

Improveelectrode formationVSAvoidcycle characteristics

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical parameters of the binder composition by incorporating specific polymer structures with nitrile groups and polyoxyethylene groups in controlled proportions. This parameter change in the binder's chemical composition improves both the ease of forming the electrode mixed material layer and the cycle characteristics of the electrochemical device, as the modified binder provides better stability during charge-discharge cycles while maintaining manufacturability.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the fibrous conductive material is dispersed in the electrode mixed material layer, then electrical conductivity is achieved, but aggregation occurs leading to increased resistance

Engineering Contradiction:

Improveelectrical conductivityVSAvoidresistance

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The binder composition acts as an intermediary that prevents direct aggregation of fibrous conductive materials. By incorporating polymers with specific functional groups, the binder creates a stable dispersion medium that separates conductive material fibers, preventing aggregation and the associated increase in electrical resistance, while still maintaining the conductivity network necessary for electrode function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the physical and chemical parameters of the binder composition, specifically the molecular structure and functional group composition of the polymers. These parameter changes in the binder enable it to effectively separate and disperse fibrous conductive materials, preventing aggregation and reducing electrical resistance while maintaining the conductivity required for electrode performance.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12479981B2Binder composition for electrochemical device, conductive material dispersion liquid for electrochemical device, slurry for electrochemical device electrode, electrode for electrochemical device, and electrochemical device

Publication Date: 2025.11.25 ZEON CORP

AI summary

Provided is a binder composition that is capable of producing a conductive material dispersion liquid having excellent dispersibility and that can cause an electrochemical device to display excellent cycle characteristics. The binder composition contains a first polymer, a second polymer, and an organic solvent. The first polymer includes a nitrile group-containing monomer unit and includes either or both of an aliphatic conjugated diene monomer unit and an alkylene structural unit. The second polymer includes a structural unit of the following formula (I) in a proportion of 70 mass % to 95 mass %. In formula (I), R1 represents a hydrogen atom or a methyl group, R2 represents a hydrogen atom, a phenyl group, an alkyl group having a carbon number of 1 to 6, or a phenyl group including one to three alkyl groups having a carbon number of 1 to 6, and n represents an integer of 3 or more.