Polyalkylene Oxide Binder for All-Solid-State Battery Ion Conductivity

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Solution Overview

Problem

All-solid-state lithium secondary batteries exhibit insufficient battery capacity and cycle characteristics due to inadequate ion conductivity in the solid electrolyte and active material layers, necessitating an improvement in battery performance.

Innovation Solution

A binder for all-solid-state secondary batteries is developed using a binder polymer obtained by polymerizing or copolymerizing a monomer composition containing a polyalkylene oxide-based monomer, which is used to form a solid electrolyte layer, enhancing the battery's characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polymer solid electrolyte is used, then the battery can be assembled, but the battery exhibits insufficient ion conductivity and poor cycle characteristics

Engineering Contradiction:
Improveion conductivityVSAvoidcycle characteristics
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent uses a composite binder system consisting of polyacrylic acid and polyethylene glycol in specific weight ratios (0.1-10:1-100). This composite material combines the binding functionality of polyacrylic acid with the ion-conducting properties of polyethylene glycol, achieving both structural integrity and high ion conductivity in the solid electrolyte layer, thereby improving both reliability and cycle characteristics

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If an inorganic solid electrolyte is used, then safety is improved, but battery capacity and cycle characteristics remain insufficient

Engineering Contradiction:
ImprovesafetyVSAvoidbattery capacity
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent optimizes the molecular weight and weight ratio of polyethylene glycol in the binder system. By adjusting these parameters, the solid electrolyte layer achieves enhanced ion conductivity and battery capacity while maintaining the safety benefits of inorganic solid electrolyte materials, resolving the contradiction between safety and performance

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If a conventional binder is used in the solid electrolyte layer, then the layer can be formed, but ion conductivity and energy density are insufficient

Engineering Contradiction:
Improvelayer formationVSAvoidenergy density
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The polyethylene glycol component serves multiple functions: it acts as a binder to hold the solid electrolyte layer together, simultaneously provides ion conduction pathways, and enhances energy density. This multi-functional binder system eliminates the need for separate components, achieving both ease of manufacture and high performance

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 binder polymer improves the battery's performance by increasing ion conductivity and energy density, resulting in better battery characteristics and cycle retention.

Implementation Method 1

insufficient ion conductivity in a solid electrolyte layer

Methodology Applied
Scientific EffectIon conductivity: Conduction (electrical)

Implementation Method 2

a binder polymer obtained by polymerizing or copolymerizing a monomer composition containing a polyalkylene oxide-based monomer

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 3

a binder polymer obtained by polymerizing or copolymerizing a monomer composition containing a polyalkylene oxide-based monomer

Methodology Applied
Scientific EffectCopolymerization: Photopolymerisation

Data Source

PatentUS10797343B2Binder for all-solid-state secondary batteries, and all-solid-state secondary battery
Publication Date: 2020.10.06 ZEON CORP

AI summary

This binder for all-solid-state secondary batteries contains a binder polymer which is obtained by polymerizing or copolymerizing a monomer composition that contains a polyalkylene oxide-based monomer.