Polyacrylamide Dispersing Agent for Li-Ion Battery Slurry

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Solution Overview

Problem

Lithium ion batteries face challenges in achieving effective dispersion of conductive carbon materials within the battery slurry, leading to inadequate conductivity and stability issues, particularly due to swelling and electrolyte resistance problems.

Innovation Solution

A conductive carbon material dispersing agent comprising a water-soluble poly(meth)acrylamide with specific molecular weight and composition, including structural units from (meth)acrylamide, unsaturated sulfonic acid, and (meth)acrylic acid ester, is used to enhance dispersion and stability in lithium ion battery electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conductive carbon material is added to the slurry, then the conductivity of the electrode is improved, but the conductive carbon material does not disperse properly in the slurry

Engineering Contradiction:

ImproveconductivityVSAvoiddispersion

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

A dispersing agent comprising a water-soluble poly(meth)acrylamide with specific structural units is introduced as an intermediary substance between the conductive carbon material and the slurry components. This dispersing agent facilitates proper dispersion of the conductive carbon material while maintaining its conductivity function, resolving the contradiction between conductivity improvement and dispersion stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The molecular weight and compositional parameters of the poly(meth)acrylamide dispersing agent are specifically controlled (weight average molecular weight and structural unit composition) to optimize both dispersion capability and compatibility with the slurry system, enabling simultaneous achievement of good dispersion and maintained conductivity.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If a dispersing agent is used to disperse conductive carbon material, then dispersion is improved, but swelling increases and electrolytic solution resistance worsens

Engineering Contradiction:

ImprovedispersionVSAvoidelectrolytic solution resistance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The molecular weight of the poly(meth)acrylamide dispersing agent is specifically controlled within a defined range. This parameter optimization ensures sufficient dispersion capability while limiting excessive swelling and maintaining favorable electrolytic solution resistance, thus resolving the contradiction between dispersion improvement and reliability maintenance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The dispersing agent is designed as a composite polymer structure containing multiple types of structural units (from specific compounds) that work synergistically: some units provide dispersion functionality while others control swelling and maintain electrolyte resistance, achieving balanced performance across conflicting requirements.

Inventive Principle:

Principle #40Composite materials

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 solution ensures favorable dispersion of conductive carbon materials, improves electrode adhesion, and maintains storage stability while retaining high electrolytic solution resistance, resulting in enhanced discharge capacity retention.

Implementation Method 1

a water-soluble poly(meth)acrylamide (A-1) which contains 2 to 60 mol % of structural units derived from a (meth)acrylamide group-containing compound (a) and 10 to 70 mol % of structural units derived from an unsaturated sulfonic acid or salts thereof (b)

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

it is preferable that the dispersing agent have characteristics of low swelling and having favorable electrolytic solution resistance with respect to the electrolytic solution of the lithium ion battery

Methodology Applied

Scientific EffectSwelling resistance:

Implementation Method 3

having favorable electrolytic solution resistance with respect to the electrolytic solution of the lithium ion battery

Methodology Applied

Scientific EffectElectrolytic solution resistance:

Data Source

PatentUS11658302B2Conductive carbon material dispersing agent for lithium ion battery, slurry for lithium ion battery electrode, electrode for lithium ion battery, and lithium ion battery

Publication Date: 2023.05.23 ARAKAWA CHEM IND LTD

AI summary

To provide a conductive carbon material dispersing agent for a lithium ion battery, a slurry for a lithium ion battery electrode, an electrode for a lithium ion battery, and a lithium ion batteryThe disclosure provides a conductive carbon material dispersing agent for a lithium ion battery including a water-soluble poly(meth)acrylamide (A-1) which contains 2 to 60 mol % of structural units derived from a (meth)acrylamide group-containing compound (a) and 10 to 70 mol % of structural units derived from an unsaturated sulfonic acid or salts thereof (b), and which has a weight average molecular weight of 10,000 to 300,000.