Block Copolymer Electrolyte for Low-Humidity Proton Conduction

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Solution Overview

Problem

Conventional block copolymers used in polymer electrolyte fuel cells exhibit insufficient power generation performance and mechanical strength under low-humidity conditions, limiting their industrial applicability.

Innovation Solution

A block copolymer with specific molecular weight ratios of ionic and non-ionic segments, incorporating an aromatic hydrocarbon polymer with a number-average molecular weight between 40,000 and 50,000, and a molecular weight ratio of Mn3 / (Mn1 + Mn2) > 1.5, enhancing power generation performance and mechanical strength under low-humidity conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional block copolymers are used as polymer electrolyte materials, then the material can be processed and manufactured, but the power generation performance and mechanical strength under low-humidity conditions are insufficient

Engineering Contradiction:

Improvepower generation performance under low-humidity conditionsVSAvoidin-process capability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the molecular weight parameters of the ionic and nonionic segments to specific ranges (Mn1: 10,000-50,000, Mn2: 5,000-20,000) and their ratio (Mn1/Mn2: 0.5-2.0), which optimizes the balance between power generation performance and processability. This parameter optimization resolves the contradiction by finding the sweet spot where both reliability and ease of manufacture are satisfied.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a block copolymer composite structure combining ionic segments (providing proton conductivity) and nonionic segments (providing mechanical strength and processability). This composite structure allows the material to simultaneously achieve good power generation performance under low-humidity conditions and acceptable in-process capability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the ionic segment molecular weight is increased to enhance power generation performance, then proton conductivity improves, but the in-process capability deteriorates

Engineering Contradiction:

Improveproton conductivityVSAvoidin-process capability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention optimizes the ionic segment molecular weight to a specific range (Mn1: 10,000-50,000) rather than using excessively high molecular weights. This parameter control ensures sufficient proton conductivity while maintaining acceptable processability, resolving the contradiction between reliability and ease of manufacture.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates local ionic domains within the block copolymer structure where proton conduction occurs, while the overall polymer matrix maintains processability. The ionic segments form conductive pathways locally without requiring the entire polymer to have high molecular weight, thus resolving the contradiction between proton conductivity and in-process capability.

Inventive Principle:

Principle #3Local quality

3Strength

If the nonionic segment molecular weight is increased to improve mechanical strength, then dimensional stability improves, but the power generation performance under low-humidity conditions deteriorates

Engineering Contradiction:

Improvedimensional stabilityVSAvoidpower generation performance under low-humidity conditions

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention optimizes the nonionic segment molecular weight to a specific range (Mn2: 5,000-20,000) and controls its ratio to the ionic segment (Mn1/Mn2: 0.5-2.0). This parameter optimization ensures sufficient mechanical strength and dimensional stability while maintaining adequate power generation performance under low-humidity conditions, resolving the contradiction between strength and reliability.

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

The block copolymer achieves high power generation performance and mechanical strength under low-humidity conditions, with improved in-process capability and physical durability, including high proton conductivity and dimensional stability.

Implementation Method 1

a block copolymer having excellent power generation performance under low-humidity conditions... high proton conductivity

Methodology Applied

Scientific EffectProton conduction: Conduction (electrical)

Implementation Method 2

an aromatic hydrocarbon polymer having a number-average molecular weight of more than 40,000 and 50,000 or less... dimensional stability

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP4588957A1Block copolymer, polymer electrolyte material using same, polymer electrolyte molded article, polymer electrolyte membrane, catalyst-coated electrolyte membrane, membrane electrode composite body, solid polymer fuel cell, and water electrolytic hydrogen generator

Publication Date: 2025.07.23 TORAY INDUSTRIES INC

AI summary

A block copolymer including one or more segments containing an ionic group (hereinafter referred to as an "ionic segment(s)") and one or more segments containing no ionic group (hereinafter referred to as a "nonionic segment(s)"), wherein the ionic segment has an aromatic hydrocarbon polymer having a number-average molecular weight of more than 40,000 and 50,000 or less, and wherein the block copolymer satisfies the relation of: Mn3 / (Mn1 + Mn2) > 1.5, wherein Mn1 represents the number-average molecular weight of the ionic segment, Mn2 represents the number-average molecular weight of the nonionic segment, and Mn3 represents the number-average molecular weight of the block copolymer. Provided is a block copolymer and a polymer electrolyte material produced using the same, wherein the block copolymer has excellent proton conductivity even under low-humidity conditions, has excellent mechanical strength and physical durability, and has an excellent in-process capability.