Sulfide Solid Electrolyte Composition Stabilization

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Solution Overview

Problem

Sulfide-based inorganic solid electrolytes used in all-solid state secondary batteries are prone to slow deterioration due to moisture, leading to a decrease in ion conductivity over time, which affects the long-term performance and reliability of these batteries.

Innovation Solution

A solid electrolyte composition with a sulfide-based solid electrolyte, a binder, and a dispersion medium is developed, where the amount of dissolved oxygen is set to 20 ppm or less, and the moisture content is kept at 50 ppm or less, using a hydrocarbon compound solvent with a branched or cyclic hydrocarbon group, and a binder with specific functional groups, to stabilize the ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sulfide-based inorganic solid electrolyte is used to achieve high ion conductivity, then ion conductivity is improved, but the electrolyte deteriorates due to moisture contact over time

Engineering Contradiction:

Improveion conductivityVSAvoidservice life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent uses a hydrocarbon compound solvent with a branched or cyclic hydrocarbon group as dispersion medium, creating an inert environment that suppresses moisture-induced deterioration of the sulfide-based solid electrolyte, thereby maintaining high ion conductivity over extended periods

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent specifies particular ranges for the hydrocarbon group (branched or cyclic) and molecular weight of the dispersion medium to optimize the balance between suppressing electrolyte deterioration and maintaining adequate ion conductivity, achieving long-term stable performance

Inventive Principle:

Principle #35Parameter changes

2Reliability

If previously dehydrated solvents are used to suppress electrolyte deterioration, then reliability is improved, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveelectrolyte stabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

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

This approach effectively suppresses the deterioration of sulfide-based solid electrolytes, maintaining high ion conductivity for a long period, enabling the stable manufacturing of all-solid state secondary batteries with improved battery performance.

Implementation Method 1

a sulfide-based solid electrolyte (A) having conductivity of ions of metals belonging to Group I or II of the periodic table

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS11621436B2Solid electrolyte composition, manufacturing method thereof, storage method thereof, kit thereof, solid electrolyte-containing sheet, storage method thereof, kit thereof, and all-solid state secondary battery

Publication Date: 2023.04.04 FUJIFILM CORP

AI summary

A solid electrolyte composition containing a sulfide-based solid electrolyte having conductivity of ions of metals belonging to Group I or II of the periodic table, a binder, and a dispersion medium, in which an amount of dissolved oxygen in the solid electrolyte composition is 20 ppm or less, a manufacturing method thereof, a storage method thereof, and a kit thereof, a solid electrolyte-containing sheet having a layer made of the solid electrolyte composition, a storage method thereof, and a kit thereof, and an all-solid state secondary battery.