Composite Binder Composition for Stable Sulfide Battery Electrode Slurries

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Solution Overview

Problem

Conventional all-solid-state batteries face challenges with sulfide-based solid electrolytes due to their high reactivity and low adhesion when using non-polar binders, which limits their binding strength and flexibility, making them unsuitable for widespread adoption.

Innovation Solution

A binder composition comprising a first polymer with a repeating structure and a second polymer, such as diene-based rubber or polysiloxane, that provides superior adhesion and flexibility without reacting with sulfide-based solid electrolytes, allowing for a wet process that reduces manufacturing costs and enhances battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a non-polar binder is used to suppress reaction with sulfide-based solid electrolyte, then chemical stability is improved, but adhesion strength deteriorates

Engineering Contradiction:

Improvechemical stabilityVSAvoidadhesion strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite binder system combining polyacrylonitrile (polar polymer) with at least one of polyvinylidene fluoride or polyvinylidene fluorocarbonate (non-polar or low-polarity polymers). This composite approach allows the polar component to provide adhesion through polar functional groups while the non-polar/low-polarity component suppresses chemical reactions with sulfide-based solid electrolytes, thereby resolving the contradiction between adhesion strength and chemical stability.

Inventive Principle:

Principle #40Composite materials

2Strength

If a polar binder is used to improve adhesion, then binding strength is improved, but reactivity with sulfide-based solid electrolyte worsens

Engineering Contradiction:

Improvebinding strengthVSAvoidreactivity with solid electrolyte

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent employs a composite binder where polyacrylonitrile (providing polar adhesion) is combined with polyvinylidene fluoride or polyvinylidene fluorocarbonate (providing chemical stability). The synergistic effect allows the polar component to deliver strong binding strength while the non-polar/low-polarity component mitigates harmful reactivity with sulfide-based solid electrolytes, resolving the contradiction between binding strength and reactivity.

Inventive Principle:

Principle #40Composite materials

3Reliability

If dry process is used for all-solid-state battery manufacturing, then battery performance is improved, but manufacturing complexity and cost worsen

Engineering Contradiction:

Improvebattery performanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The composite binder acts as an intermediary that enables the transition from dry process to wet process manufacturing. By providing both adhesion and chemical stability, the binder allows electrode slurries to be used in wet coating processes, simplifying manufacturing while maintaining battery performance characteristics.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11777094B2Composite binder composition for all-solid-state battery, electrode slurry comprising same, and method of manufacturing electrode for all-solid-state battery using electrode slurry

Publication Date: 2023.10.03 HYUNDAI MOTOR CO LTD

AI summary

A composite binder composition for an all-solid-state battery includes: a first polymer comprising a repeating structure represented by Chemical Formula 1a or Chemical Formula 1b below, and a second polymer comprising at least one selected from a group consisting of diene-based rubber, polysiloxane, and combinations thereof: