Negative Electrode Polymer Interface for Solid-State Battery Ion Conduction

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Solution Overview

Problem

Existing batteries face challenges in securing a good ion conduction state and durability due to the rigidity of solid electrolytes, which can cause poor contact at the interface with negative electrode active materials, and binders do not exhibit sufficient metal ion transference numbers.

Innovation Solution

A battery design incorporating a negative electrode active material layer and a solid electrolyte layer with a phosphorus-carbon composite material and a polymer that preferentially conducts metal ions, ensuring good ion conduction and high durability by using a phosphorus-carbon composite material and a polymer with anionic functional groups or anion-trapping ability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solid electrolyte is used, then ion conductivity and safety are improved, but contact at the interface with the negative electrode active material deteriorates due to rigidity

Engineering Contradiction:

Improveion conductivity and safetyVSAvoidcontact at interface

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies local quality by introducing a polymer with metal ion transference capability specifically at the interface region between the solid electrolyte and negative electrode active material. This localized modification allows the bulk solid electrolyte to maintain its rigidity and high ion conductivity, while the interfacial polymer layer provides flexibility and good contact with the electrode material, thus resolving the contradiction between rigidity and contact quality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining the solid electrolyte with a polymer that has metal ion transference capability. This composite structure integrates the advantages of both materials: the solid electrolyte provides high ion conductivity and safety, while the polymer component enhances interfacial contact and metal ion transference number, thereby resolving the contradiction between rigidity and contact quality.

Inventive Principle:

Principle #40Composite materials

2Strength

If a binder is used in the negative electrode, then structural integrity is improved, but metal ion transference number deteriorates due to insufficient transference capability

Engineering Contradiction:

Improvestructural integrityVSAvoidmetal ion transference number

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by selecting a polymer with specific functional characteristics (metal ion transference capability) to replace conventional binders. This changes the key parameter of metal ion transference number from insufficient (in traditional binders) to high (in the polymer), while simultaneously maintaining structural integrity through the polymer's binding properties.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by replacing the traditional binder with a polymer that has both binding functionality and metal ion transference capability. This composite approach allows the negative electrode to maintain structural integrity through the polymer's adhesion properties while achieving high metal ion transference number through the polymer's ionic conductivity, thus resolving the contradiction between structural integrity and metal ion transference.

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 design achieves a stable ion conduction state and improved battery durability by enhancing metal ion transference and preventing dendrite growth, with the polymer providing better contact and conductivity than traditional binders and electrolytes.

Implementation Method 1

any one or both of the negative electrode active material layer and the solid electrolyte layer contain a polymer having an ability to preferentially conduct metal ions

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

in a case where an alkali metal is used as a counter electrode and 0.1 V or higher is applied, occludes or releases ions of the alkali metal

Methodology Applied

Scientific EffectIon occlusion and release: Absorption (physical)

Data Source

PatentEP4614624A1Negative electrode material, laminate, and battery

Publication Date: 2025.09.10 SUMITOMO CHEM CO LTD

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AI summary

A battery including: a negative electrode having a negative electrode active material layer; and a solid electrolyte layer that is in contact with the negative electrode active material layer, in which the negative electrode active material layer contains a negative electrode active material that, in a case where an alkali metal is used as a counter electrode and 0.1 V or higher is applied, occludes or releases ions of the alkali metal, and any one or both of the negative electrode active material layer and the solid electrolyte layer contain a polymer having an ability to preferentially conduct metal ions.