All-solid-state battery electrolyte segmentation for decomposition

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Solution Overview

Problem

Sulfide solid electrolyte materials with cross-linking chalcogens in all-solid-state batteries are prone to decomposition when reacting with positive electrode active materials, leading to low durability and ionic conductivity issues.

Innovation Solution

Incorporating a first sulfide solid electrolyte material without cross-linking chalcogens in the positive electrode active material layer and a second sulfide solid electrolyte material with cross-linking chalcogens in the solid electrolyte layer, specifically using materials like Li2S and P or Ge, to reduce decomposition and enhance ionic conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sulfide solid electrolyte material with cross-linking chalcogen is used, then ionic conductivity is improved, but durability deteriorates due to decomposition reaction with positive electrode active material

Engineering Contradiction:

Improveionic conductivityVSAvoiddurability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The battery is divided into two distinct layers: a first sulfide solid electrolyte layer in contact with the positive electrode that lacks cross-linking chalcogens, and a second sulfide solid electrolyte layer that contains cross-linking chalcogens but is positioned away from the positive electrode. This segmentation allows each layer to fulfill its specific function without the harmful interaction between cross-linking chalcogens and the positive electrode active material.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the electrolyte system are assigned different material properties. The first layer near the positive electrode has the quality of being free from cross-linking chalcogens to prevent decomposition, while the second layer has the quality of containing cross-linking chalcogens to provide high ionic conductivity. This local differentiation resolves the contradiction by placing the right material quality in the right location.

Inventive Principle:

Principle #3Local quality

2Temperature

If sulfide solid electrolyte material with cross-linking chalcogen is used, then high-temperature storability is improved, but decomposition occurs when contacting positive electrode active material

Engineering Contradiction:

Improvehigh-temperature storabilityVSAvoiddecomposition reaction

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The electrolyte system is segmented into two layers with different chemical compositions. The first layer lacks cross-linking chalcogens and serves as a protective barrier against the positive electrode, preventing decomposition reactions. The second layer contains cross-linking chalcogens that provide high-temperature storability, positioned where they will not contact the positive electrode active material.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first sulfide solid electrolyte layer acts as an intermediary barrier between the positive electrode active material and the second sulfide solid electrolyte layer containing cross-linking chalcogens. This intermediary layer prevents direct contact and harmful decomposition reactions while allowing the second layer to provide its beneficial high-temperature storability properties.

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

This configuration results in an all-solid-state battery with improved durability, normal-temperature, and high-temperature storability, along with increased output and reduced interface resistance, thereby enhancing the battery's overall performance.

Implementation Method 1

a first sulfide solid electrolyte material that contacts the positive electrode active material... since the first sulfide solid electrolyte material is employed in the positive electrode active material layer, the contact between the positive electrode active material and the second sulfide solid electrolyte material can be restrained

Methodology Applied

Scientific EffectPhysical barrier / Contact prevention:

Implementation Method 2

a solid electrolyte layer that is provided between the positive electrode active material layer and the negative electrode active material layer, and that contains a second sulfide solid electrolyte material

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS8557445B2All solid state battery containing an electrolyte comprising chalcogens

Publication Date: 2013.10.15 TOYOTA JIDOSHA KK

AI summary

An all-solid-state battery includes: a positive electrode active material layer that contains a positive electrode active material, and a first sulfide solid electrolyte material that contacts the positive electrode active material and that substantially does not have a cross-linking chalcogen; a negative electrode active material layer containing a negative electrode active material; and a solid electrolyte layer that is provided between the positive electrode active material layer and the negative electrode active material layer, and that contains a second sulfide solid electrolyte material that substantially has a cross-linking chalcogen.