Ketone Dispersion Medium for Solid Battery Electrodes

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Solution Overview

Problem

Existing compositions for forming active material layers in all-solid state secondary batteries face challenges in achieving sufficient dispersibility of sulfide-based solid electrolytes and conductive auxiliary agents, leading to decreased conductivity and battery capacity due to aggregation and deterioration of the sulfide-based solid electrolyte.

Innovation Solution

A composition using a ketone compound dispersion medium with aliphatic groups bonded to a carbonyl group, specifically with branched chain structures, is employed to disperse sulfide-based solid electrolytes and carbonaceous conductive auxiliary agents, preventing aggregation and deterioration, thereby enhancing ion and electron conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a non-aqueous dispersion medium or non-polar dispersion medium is used to prevent deterioration of sulfide-based solid electrolyte, then the stability of sulfide-based solid electrolyte is improved, but the dispersibility of carbonaceous conductive auxiliary agent deteriorates

Engineering Contradiction:

Improvestability of sulfide-based solid electrolyteVSAvoiddispersibility of carbonaceous conductive auxiliary agent

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent introduces a specific dispersant as an intermediary substance that mediates between the non-polar dispersion medium and the carbonaceous conductive auxiliary agent. The dispersant has a molecular structure with both polar and non-polar characteristics, allowing it to compatibilize the hydrophobic carbonaceous material with the non-polar dispersion medium while preventing aggregation, thus resolving the contradiction between maintaining electrolyte stability and achieving good dispersibility

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a composite dispersion system consisting of non-polar dispersion medium combined with specifically designed dispersant molecules. This composite approach creates a multi-functional dispersion medium that simultaneously provides the hydrophobic environment needed for sulfide-based solid electrolyte stability while incorporating dispersing agents that enable effective dispersion of carbonaceous conductive auxiliary agents

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If conventional dispersion media are used to disperse sulfide-based solid electrolyte, then the stability is maintained, but aggregation occurs and conductivity decreases

Engineering Contradiction:

Improvestability of sulfide-based solid electrolyteVSAvoidconductivity of electrode active material layer

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The dispersant acts as a mediator that prevents aggregation of sulfide-based solid electrolyte particles in the non-polar dispersion medium. By adsorbing onto particle surfaces and providing steric or electrostatic repulsion, the dispersant maintains individual particle separation, ensuring both stability and high conductivity of the resulting electrode active material layer

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If carbonaceous material is used as conductive auxiliary agent, then electron conductivity is improved, but aggregation occurs and dispersibility decreases

Engineering Contradiction:

Improveelectron conductivityVSAvoiddispersibility

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The dispersant serves as a critical intermediary between the hydrophobic carbonaceous conductive auxiliary agent and the dispersion medium. The dispersant molecules adsorb onto carbonaceous material surfaces, providing steric hindrance and electrostatic repulsion that prevent aggregation, thereby maintaining high electron conductivity while achieving uniform dispersion in the electrode active material layer

Inventive Principle:

Principle #24Intermediary (Mediator)

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 composition achieves high ion and electron conductivity, ensuring a sufficient battery capacity by effectively dispersing the sulfide-based solid electrolyte and conductive auxiliary agents, preventing re-aggregation and deterioration, and maintaining excellent dispersion states during the manufacturing process.

Implementation Method 1

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

the dispersion medium includes at least one ketone compound dispersion medium in which two aliphatic groups each having 4 or more carbon atoms are bonded to a carbonyl group

Methodology Applied

Scientific EffectSolvation: Solvation

Data Source

PatentUS11658282B2Composition for forming active material layer and method for manufacturing the same, and methods for manufacturing electrode sheet for all-solid state secondary battery and all-solid state secondary battery

Publication Date: 2023.05.23 FUJIFILM CORP

AI summary

A composition for forming an active material layer, including a sulfide-based solid electrolyte, an active material, a conductive auxiliary agent including a carbonaceous material, and a dispersion medium, in which the dispersion medium includes at least one ketone compound dispersion medium in which two aliphatic groups each having 4 or more carbon atoms are bonded to a carbonyl group; a method for manufacturing the composition for forming an active material layer; a method for manufacturing a solid electrolyte-containing sheet; and a method for manufacturing an all-solid state secondary battery.